Disposable single-use external dosimeters for detecting radiation in fluoroscopy and other medical procedures/therapies

ABSTRACT

Methods, systems, devices, and computer program products include positioning single-use radiation sensor patches that have adhesive onto the skin of a patient to evaluate the radiation dose delivered during a medical procedure or treatment session. The sensor patches are configured to be relatively unobtrusive and operate during radiation without the use of externally extending power cords or lead wires.

RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.10/865,430, filed Jun. 10, 2004, which is a continuation-in-part of U.S.patent application Ser. No. 10/303,591, filed Nov. 25, 2002, whichclaims priority from U.S. Provisional Patent Application Ser. No.60/334,580, entitled Disposable Single-Use External Dosimeters for Usein Radiation Therapies, filed Nov. 30, 2001, the contents of which arehereby incorporated herein by reference.

FIELD OF THE INVENTION

The present invention generally relates to the assessment orquantitative evaluation of the amount of radiation exposure delivered toa patient undergoing therapy.

RESERVATION OF COPYRIGHT

A portion of the disclosure of this patent document contains material towhich a claim of copyright protection is made. The copyright owner hasno objection to the facsimile reproduction by anyone of the patentdocument or the patent disclosure, as it appears in the Patent andTrademark Office patent file or records, but reserves all other rightswhatsoever.

BACKGROUND OF THE INVENTION

Conventionally, medical procedures such as, but not limited to,fluoroscopy procedures and/or radiation therapies are carried out overone or a successive series of treatment sessions. For radiationtherapies, high-energy photons and/or electrons are carefully directedand/or focused from an ex vivo radiation source so that they travel intoa targeted treatment area in a patient's body. The size, shape, andposition of the treatment area (typically where a tumor is or was) aswell as its anatomical location in the body and its proximity tosensitive normal tissues are considered when generating a particularpatient's treatment plan. That is, the treatment is planned so as todeliver a suitably high dose of radiation to the tumor or targetedtissue while minimizing the dose to nearby sensitive tissue thattypically cannot be completely avoided. Directing radiation intonon-affected regions may produce undesired side effects particularly asit relates to tissue that may be sensitive to certain dosages ofradiation. Unfortunately, even when the patient plan is carefullyconstructed to account for the location of the cancerous tissue and thesensitive non-affected regions, even small errors in set-up due to beamangle or patient position during delivery of the radiation therapy caninadvertently misdirect radiation into those regions or can influencethe dose amount that is actually received by the targeted tissue.Further, the demand for radiation treatment equipment is typicallyrelatively high and this demand may limit the set-up time allowed orallocated in the treatment room between patients.

Similarly, during fluoroscopic procedures, particularly prolongedinterventional procedures and/or over multiple procedures, a patient canbe subjected to high radiation exposures. The radiation dose depends onthe type of procedure, the size of the patient, the protocol employedand other factors. Management of patient exposure is desirable. SeeMahadevappa Mahesh, Fluoroscopy: Patient Radiation Exposure Issues,RadioGraphics, 21 (4):1033-1045 (2001).

In the past, implantable devices for oncology applications have beenproposed to evaluate the radiation dose amount received in vivo at thetumor site. See, e.g., U.S. Pat. No. 6,402,689 to Scarantino et al., thecontents of which are hereby incorporated by reference herein. Measuringthe radiation at the tumor site in vivo can provide improved estimatesof doses received. However, for certain tumor types or situations,including certain fluoroscopic procedures, one or more skin-mounted orexternal surface radiation dosimeters may be desirable and sufficientfor clinical purposes.

Conventional external or skin-mounted radiation dosimeter systems usesemiconductor circuitry and lead wires that power/operate thedosimeters. These types of dosimeters are available from Scandatronicsand/or IBA (“Ion Beam Applications”) having an internationalheadquarters location in Belgium. While these radiation dosimetersystems may provide radiation dose estimations, they can, unfortunately,be relatively expensive. Further, these types of dosimeters are used fora plurality of patients potentially raising sterility or cleanlinessproblems between patients. Conventional dosimeter systems may alsorequire substantial technician time before and during the radiationsession. For example, conventional dosimeter systems need to becalibrated before the radiation session may begin. In addition, the leadwires can be cumbersome to connect to the patients and may requireexcessive set-up time, as the technician has to connect the lead wiresto run from the patient to the monitoring system and then store the leadwire bundle between patient treatment sessions. Therefore, techniciansdo not always take the time to use this type of system, and noconfirmation estimate of the actual radiation delivered is obtained.

Other radiation sensors include thermo-luminescent detectors (TLD's).However, while TLD detectors do not require wires during operation, theyare analyzed using a spectrophotometer (that may be located in anoffsite laboratory) and are not conducive to real-time readings.

In view of the foregoing there remains a need for improved economicaland easy to use radiation dosimeters.

SUMMARY OF EMBODIMENTS OF THE INVENTION

Certain embodiments are directed a cost-effective surface mountradiation dosimeter that can be used to evaluate radiation dose exposuredelivered to a patient undergoing therapy.

Certain embodiments of the present invention to provide economic methodsand devices that can reduce labor set-up time in the treatment chamberover conventional evaluation methods and devices.

Other embodiments of the present invention provide a memory storagedevice on a radiation dosimeter patch to record the dose history of thepatch. This memory storage device may be queried at any time in order toobtain a record of the dose applied to the patch. Other information,such as patient identification, time, date, hospital, therapist, stateof the device, dosed/undosed and calibration data may be stored in thememory storage device.

Certain embodiments of the present invention to provide an economicmethod of determining the amount of radiation delivered to an oncologypatient in situ and/or patients undergoing fluoroscopic and/or radiationtherapies.

Embodiments of the present invention are directed to a disposable,single-use skin mounted radiation dosimeter that has a self-containedpackage that can be adhesively attachable to the skin of the patient,and operates in a relatively easy to operate and read manner withoutrequiring the use of lead wires (or even power) during irradiation.

Certain embodiments of the present invention are directed to methods formonitoring radiation doses administered to patients undergoing treatmentand/or a medical procedure. The methods include: (a) releasably securingat least one single-use dosimeter sensor patch onto the skin of thepatient, wherein the patch is self-contained; (b) exposing the patientto radiation in a medical procedure, wherein the at least one patchcomprises a MOSFET-based radiation sensor circuit that is unpoweredduring radiation exposure; (c) transmitting data from the sensor patchto a dose-reader device after the exposing step to obtain dataassociated with a change in an operational parameter in the dosimetersensor patch; and (d) determining radiation received by the patientduring the exposing step based on the change in the operationalparameter.

The at least one patch may include a first patch that comprises aplurality of spaced apart radiation sensors, each radiation sensorcomprising a single-MOSFET. The patch can be positioned on the patientso as to place at least one of the radiation sensors held on the firstpatch in a location that is generally medial to a projected radiationbeam path used in a fluoroscopic procedure.

In some embodiments, the sensor patch may be pre-dosed and/or calibratedbefore the sensor patch is secured to the patient. The obtained data maybe stored in an electronic storage device provided on the sensor patchitself. The storage device may be, for example, an EEPROM. Otherinformation, such as the patient's name, the doctor's name, the test ortreatment date and the like, may also be stored in the storage deviceprovided on the sensor patch. Alternatively, the data can be stored on acomputer readable memory integrated on a physical record sheet that canbe placed in the patient's file.

Other embodiments are directed to systems for monitoring radiationadministered to a patient during a therapeutic treatment. The systemsinclude: (a) at least one single-use dosimeter patch, the patchcomprising a substantially conformable body holding at least oneMOSFET-based radiation sensor circuit, electronic memory having a storedcalibration coefficient for determining radiation dose, the MOSFEThaving an associated threshold voltage that changes when exposed toradiation; and (b) a portable dose-reader configured to obtain voltagethreshold data from the at least one patch corresponding to a doseamount of radiation exposure received during irradiation exposure.During irradiation, the at least one patch has a perimeter that isdevoid of outwardly extending lead wires.

In some embodiments, the at least one patch can include a primary sensorpatch and a secondary sensor patch with the primary sensor patchconfigured with a larger surface area than the secondary sensor patch.The primary patch can include a plurality of spaced apart radiationsensor circuits, each having a respective one MOSFET. Each MOSFET inrespective radiation sensor circuits can be configured to independentlydetect radiation.

In some embodiments, the patch includes a conformable resilient body.The lower primary surface may include a medical grade adhesive and thesensor patch may be pressed on to secure the sensor patch to thepatient. In other embodiments, an adhesive coverlay is applied over thesensor patch to secure the sensor to the patient. A portion, or all, ofthe sensor patch may be adapted to be inserted into the dose-reader totransmit the dose data and the dose-reader may similarly be adapted toreceive a portion or all of the sensor patch. Insertion of the sensorpatch into the reader electrically couples the sensor to the reader andallows the reader to receive the radiation dose data from the sensorpatch. In particular embodiments, the patch may be inductively powered.

Still other embodiments are directed to sterile medical kits ofsingle-use external use radiation dosimeter patches. The kit can includea plurality of single-use patches. Each patch can include a generallyconformable resilient substrate body comprising opposing upper and lowerprimary surfaces, a flex circuit with at least one operationalelectronic component that changes a parameter in a detectablepredictable manner when exposed to radiation. The flex circuit is heldby the substrate body. The patch also includes at least one electronicmemory in communication with the at least one operational electroniccomponent held by the substrate body. In position on a patient duringradiation exposure, the dosimeter patches are devoid of externallyextending lead wires, and wherein the patches are single-use dosimeterpatches that adhesively secure to the skin of a patient.

Still other embodiments are directed to fluoroscopic single-useradiation dosimeter patches. The patches have a generally conformableresilient body holding at least one radiation sensor circuit with aMOSFET that changes a parameter in a detectable predictable manner whenexposed to radiation. During irradiation, the patch is devoid ofexternally extending lead wires.

In some embodiments, the patch has a surface area that is sufficient tocover a major portion of a predicted surface exposure area associatedwith a target radiation beam path (typically having a surface area ofbetween about 4-35 cm). The patch can include a plurality of spacedapart radiation sensor circuits, each having a respective MOSFET.

Another embodiment is directed to a computer program product forevaluating a radiation dose delivered to a patient. The computer programproduct comprises a computer readable storage medium having computerreadable program code embodied in the medium. The computer-readableprogram code comprises: (a) computer readable program code for receivingpre-irradiation threshold voltage data associated with a disposablesensor patch having a plurality of spaced apart radiation sensorcircuits thereon; (b) computer readable program code for directing areader to communicate with the patch to obtain radiation data from aplurality of different radiation sensor circuits held on the sensorpatch; and (c) computer readable program code for determining thevoltage threshold shift of the radiation sensor circuits on thedisposable sensor patch after radiation to determine the radiationexposure.

In still further embodiments of the present invention, a dose-reader maybe adapted to receive a sensor patch in a sensor port. The sensor patchis also adapted to be inserted in the sensor port. The dose-reader canbe a pocket or palm sized portable device. The dose-reader may alsoinclude a communications port, for example, a universal serial port(USB), RS 232 and the like, for downloading obtained data to a computerapplication or remote computer. The dose-reader functionality may beincorporated into a personal digital assistant (PDA) or other pervasivecomputer device.

In further embodiments the sensor patch may be configured to communicatewith the dose-reader wirelessly. For example, the sensor patch and thedose-reader may both be equipped with a radio frequency (RF) interfaceso that information may be shared between the two devices.

The foregoing and other objects and aspects of the present invention areexplained in detail in the specification set forth below.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic illustration of a patient undergoing radiationtreatment according to some embodiments of the present invention.

FIG. 2 is a block diagram of operations for monitoring patientsundergoing radiation treatments according to further embodiments of thepresent invention.

FIGS. 3A and 3B are illustrations of sets of disposable dosimeterpatches according to still further embodiments of the present invention.

FIG. 3C is an anatomical map of sensor location according to someembodiments of the present invention.

FIG. 4 illustrates an exemplary patient information form according tosome embodiments of the present invention.

FIGS. 5A and 5B are schematic illustrations of sensor placement on apatient according to further embodiments of the present invention.

FIG. 6 is a schematic illustration of embodiments of a reader contactingthe sensor to obtain the radiation dosage data according to stillfurther embodiments of the present invention.

FIG. 7A is a schematic illustration of further embodiments of a readerreceiving the sensor in a sensor port to obtain the radiation dosagedata according to some embodiments of the present invention.

FIG. 7B is a schematic illustration of still further embodiments of areader receiving wireless communications from the sensor to obtain theradiation dosage data according to further embodiments of the presentinvention.

FIG. 8A is a greatly enlarged side view of a disposable radiationdosimeter according to still further embodiments of the presentinvention.

FIG. 8B is a top view of the dosimeter shown in FIG. 8A.

FIG. 8C is a partial cutaway view of a probe head for a reader accordingto some embodiments of the present invention.

FIG. 9A is a schematic of embodiments of a sensor patch with a circuitthereon according to further embodiments of the present invention.

FIG. 9B is a schematic of further embodiments of a sensor patch with acircuit thereon according to still further embodiments of the presentinvention.

FIG. 9C is a schematic of further embodiments of a sensor patch with acircuit thereon according to some embodiments of the present invention.

FIG. 9D is a schematic of further embodiments of a sensor patchaccording to further embodiments of the present invention.

FIG. 9E is a schematic of further embodiments of a sensor patchaccording to still further embodiments of the present invention.

FIG. 10A is a schematic illustration of a sheet of sensors according tosome embodiments of the present invention.

FIG. 10B is yet another schematic illustration of a sheet of sensorsaccording to further embodiments of the present invention.

FIG. 10C is a further schematic illustration of a sheet of sensorsaccording to still further embodiments of the present invention.

FIG. 10D is still a further schematic illustration of a sheet of sensorpatches according to some embodiments of the present invention.

FIG. 11 is a schematic of a circuit diagram of a MOSFET sensor with areader interface and an optional memory according to some embodiments ofthe present invention.

FIG. 12A is a schematic of a threshold voltage reader circuit accordingto further embodiments of the present invention.

FIG. 12B is a graph of the change in the threshold voltage value versusradiation dose according to still further embodiments of the presentinvention.

FIG. 13 is a graph of the threshold voltage dependence on Ids using thevoltage (V₀) of the reader illustrated in FIG. 12A.

FIG. 14A is a schematic of a circuit diagram with a MOSFET pair, theleft side of the figure corresponding to an irradiation operativeconfiguration and the right side of the figure corresponding to a readdose operative configuration, according to some embodiments of thepresent invention.

FIG. 14B is a schematic of a circuit diagram with a MOSFET pair, theleft side of the figure corresponding to an irradiation operativeconfiguration and the right side of the figure corresponding to a readdose operative configuration, according to further embodiments of thepresent invention.

FIG. 15A is a schematic of a system or computer program product forestimating radiation based on data taken from a point contact-readerdata acquisition system according to still further embodiments of thepresent invention.

FIG. 15B is a block diagram illustrating a reader device according tosome embodiments of the present invention.

FIG. 15C is a block diagram illustrating a reader device according tofurther embodiments of the present invention.

FIG. 16 is a block diagram of a computer program having a radiationestimation module according to still further embodiments of the presentinvention.

FIG. 17 is a block diagram of a point-contact reader data acquisitionsystem some according to embodiments of the present invention.

FIGS. 18A and 18B are schematic diagrams illustrating buildup capsaccording to further embodiments of the present invention.

FIG. 19 is a table including sensor specifications according to furtherembodiments of the present invention.

FIG. 20 is a block diagram illustrating functions of a reader device anda patch according to some embodiments of the present invention.

FIG. 21 is a block diagram illustrating a process for modifyingconversion parameters and bias timing according some embodiments of thepresent invention.

FIG. 22 is a schematic diagram of a test strip according to furtherembodiments of the present invention.

FIG. 23 is a calibration curve illustrating a dose response of anexemplary MOSFET/RADFET according to still further embodiments of thepresent invention.

FIG. 24 is a graph illustrating an exemplary correction factor forenergy dependence according to some embodiments of the presentinvention.

FIG. 25 is a table illustrating exemplary “k-factors” that may beapplied to a dose equation according to further embodiments of thepresent invention.

FIG. 26 is a table illustrating an order of storing temperaturecorrection coefficients according to still further embodiments of thepresent invention.

FIG. 27 is a table illustrating an order of storing fade correctioncoefficient according to some embodiments of the present invention.

FIG. 28 is a graph illustrating an exemplary response for fade in theRADFET voltage following a dose application according to furtherembodiments of the present invention.

FIG. 29 is a table including V/I relationships of readers according tostill further embodiments of the present invention.

FIG. 30 is a table including a list of items included in an exemplarydose record according to some embodiments of the present invention.

FIG. 31 is a table including functional specifications of test stripsaccording to further embodiments of the present invention.

FIGS. 32A and 32B are a table including functional specifications ofreaders according to still further embodiments of the present invention.

FIG. 33 is a table including functional specifications of patchesaccording to some embodiments of the present invention.

FIG. 34A is a top schematic view of a multi-sensor patch according toembodiments of the present invention.

FIG. 34B is a side view of the patch shown in FIG. 34A,

FIG. 35 is a top view of an alternate multi-sensor patch according toembodiments of the present invention.

FIG. 36 is a schematic top view of another embodiment of a multi-sensorpatch in position on a patient according to yet other embodiments of thepresent invention.

FIG. 37A is a schematic top view of two multi-sensor patch according toyet other embodiments of the present invention.

FIG. 37B is a schematic top view of another multi-sensor patch accordingto embodiments of the present invention.

FIG. 38 is a schematic top view of another multi-sensor patch and asingle sensor patch according to yet other embodiments of the presentinvention.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The present invention will now be described more fully hereinafter withreference to the accompanying figures, in which embodiments of theinvention are shown. This invention may, however, be embodied in manydifferent forms and should not be construed as limited to theembodiments set forth herein. Like numbers refer to like elementsthroughout. In the figures, certain components, features, or layers maybe exaggerated for clarity. In the block diagrams or flow charts, brokenlines indicate optional operations, or features unless stated otherwise.As used herein, the term “and/or” includes any and all combinations ofone or more of the associated listed items.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andshould not be interpreted in an idealized or overly formal senseexpressly so defined herein.

With reference to certain particular embodiments, the description of aradiation sensor circuit having a single operative MOSFET means that thecircuit may include a semiconductor component that has more than oneMOSFET thereon/therein (as sold), but only a single MOSFET isoperatively required to obtain the radiation data for a single radiationsensor circuit (no biasing of a pair of MOSFETS is required to obtainthe radiation data).

The statements characterizing one or more of the priority applicationsas a “continuation-in-part” application of a prior application listedunder the “Related Applications” section above is used to indicate thatadditional subject matter was added to the specification of the priorapplication but does not necessarily mean that the entire inventiondescribed and claimed in the present application is not supported infull by the prior application(s).

FIG. 1 illustrates an example of a radiation system 10 with a radiationbeam source 20 directed at a patient 50 having a tumor site. The patient50 can be positioned so as to be aligned and stationary with respect tothe beam 20 b (illustrated by the diverging dotted lines) during thetreatment. As such, the patient 50 can be arranged in any desiredposition depending on the direction of the beam, the location of thetumor, and the type of radiation therapy system employed. As shown, thepatient is reclined, substantially flat and face up on a table so thatthe beam 20 b is directed into the targeted tumor site in the body asthe patient undergoes radiation therapy in a treatment session.Typically, the patient will undergo a plurality of successive treatmentsessions over a treatment period. Each treatment session may be plannedto administer radiation doses of between about 1-2 Gray (100-200 cGy)with an overall treatment limit of about 35-80 Gray.

In other embodiments, radiation is delivered during alternative medicalprocedures or treatment sessions, such as during fluoroscopy procedures.

To help monitor or estimate the amount of radiation that is delivered tothe patient during a treatment session, at least one disposablesingle-use dosimeter sensor patch 30 can be positioned externally on theskin of the patient 50. As used herein, “single-use” is used to refer toa use for a single patient during a treatment session. The sensor patch30 is typically worn once proximate in time and during a treatment.However, in some other embodiments, the sensor patch 30 may beepisodically worn or continuously worn over a target period. It will beunderstood that a treatment session may include an active radiotherapyadministration during a single treatment session or serially spacedapart treatment sessions. The treatment session may have a duration ofminutes, hours, days and the like. Furthermore, a calibration doseobtained before the sensor patch 30 is positioned on a patient is not tobe considered the “single-use.”

As shown in FIG. 1, a plurality of sensor patches 30 are located both onthe front and back of the patient 50. The sensor patches 30 areconfigured to change an operational parameter in a predictable mannerthat correlates to radiation dose it receives, as will be discussedfurther below. The sensor patch 30 can be configured so as to beself-contained and discrete and devoid of dangling lead wires extendingto a remote power source or operating system during irradiation inposition on the patient. As such, a reader, for example, reader 75(FIGS. 6 and 7), can be configured to obtain the data from the sensorpatch 30 by, for example, electrically contacting each sensor patch 30of interest. An example of one embodiment of a suitable portable readeris shown in U.S. Design patent application Ser. No. 29/197934, filedJan. 20, 2004, the contents of which are hereby incorporated byreference as if recited/shown in full herein.

As used herein, the reference number “75” will be used to refergenerally to a reader device according to embodiments of the presentinvention. Particular embodiments of a reader device 75 may be referredto using the reference number 75 and one or more primes attachedthereto. For example, particular embodiments of the reader device may bedenoted 75′ or 75″. This convention may similarly be used with respectto other features of the present invention. For example, the referencenumber “30′” will be used to refer to particular embodiments of a sensorpatch herein. It will be understood that features discussed with respectto any embodiment of the present invention may be incorporated intoother embodiments of the present invention even if these features arenot discussed specifically with reference to each individual embodiment.

Referring to FIG. 2, operations that can be carried out to monitor theradiation dose that is delivered to a patient undergoing radiationtherapy are illustrated. At least one single-use dosimeter sensor patchcan be releasably secured to the skin of the patient (block 100). Incertain embodiments, the sensor patch may be calibrated and/or pre-dosedbefore being attached to the patient (block 101). The calibration and/orpre-dosing of the sensor patch may be done on an individual patch basisor many sensor patches may be calibrated and/or pre-dosed in batchessimultaneously as discussed further below. In certain embodiments, thepatch(es) can be conveniently attached to the patient in operation-readycondition before the patient enters the radiation treatment room orchamber (block 102) to limit or reduce the set-up time required or the“down-time” of the equipment or the treatment room. In other words, thesensor patch or patches may be secured to the patient prior to his/herentry into the radiation treatment room. A pre-irradiation or pre-dosemeasurement or reading of data associated with an operational parameterof the sensor patch(es) 30 can be obtained prior to initiation of theradiation treatment (block 105). The data can be obtained in situ, withthe sensor patch(es) 30 in position on the patient. Alternatively, thepre-dose data can be established prior to positioning the sensorpatch(es) onto the subject as discussed above and the data thentransferred to the reader or associated controller and/or computer at adesired time.

In certain embodiments of the sensor patch(es), the post-radiationreading can be taken when the patient leaves the treatment room toevaluate the dose delivered during the treatment session to limit theamount of room-use time. The sensor patches 30 can be removed from thepatient and then read by a handheld portable or a bench top reader. Inother embodiments, the reading can be obtained while the sensor patches30 remain on the patient. In certain particular embodiments, the readingmay be able to be obtained in situ during the treatment session (withoutremoving the sensor patch(es) from the patient) to provide real-timefeedback to the clinician estimating whether the desired dose is beingadministered to the patient. In certain embodiments, the temperature ofthe sensor patch (such as at a location adjacent the circuitry) or ofthe subject (skin or core body) can also be ascertained or obtained andtaken into account when calculating the radiation dose. In any event thedose reading can be obtained without requiring external powering orexternally applied biasing of the sensor patches 30 during the radiationtreatment.

In certain embodiments, a plurality of discrete sensor patches 30 can bepositioned to cover a region on the skin that is in the radiation beampath so as to reside over the tumor site. In particular embodiments, oneor more sensor patches 30 can also be positioned in radiation sensitiveareas of the body to confirm stray radiation is not unduly transmittedthereto. FIG. 1 illustrates that a sensor patch can be located at theneck over the thyroid when the tumor site is over the chest region. Assuch, sensitive regions include, but are not limited to, the thyroid,the spine, the heart, the lungs, the brain, and the like.

In any event, referring again to FIG. 2, radiation is administered tothe patient in a first treatment session (block 110). Data associatedwith a change in an operational parameter in the dosimeter sensor patchcircuitry may be obtained from the sensor patch using a reader device(block 120) after administering the radiation to the patient (block110). In certain embodiments, a sensor patch may be removed from thepatient and inserted into the reader device to transfer the data fromthe sensor patch. In further embodiments, the reader device may contactthe sensor patch as discussed further below. In still furtherembodiments, the reader may transfer data from the sensor patchwirelessly. The radiation dose received by the patient can be determinedbased on the obtained data (block 125).

In some embodiments of the present invention, the obtained data mayinclude a voltage threshold of a metal-oxide semiconductor field-effecttransistor (MOSFET) included on the at least one sensor patch 30. Inthese embodiments of the present invention, a pre-radiation voltagethreshold of the MOSFET and a zero temperature coefficient of the MOSFETmay be measured before the patient undergoes radiation therapy (block108). The pre-radiation threshold voltage and the zero temperaturecoefficient of the MOSFET may be stored in the electronic memory of theat least one sensor patch (blocks 109 and 130). The stored zerotemperature coefficient may be used to bias the MOSFET (block 124) onthe at least one sensor patch 30 after the patient undergoes radiationtherapy and before the post-radiation threshold voltage is measured asdiscussed further below.

It will be understood that the radiation dose may be automaticallydetermined by the reader 75 without any input by a doctor, technician orother clinician. However, in some embodiments of the present invention,the clinician may be prompted for additional information (block 123) bythe reader 75 to determine the radiation dose. For example, the reader75 may prompt the clinician for a correction factor related to thesensor patch 30 and/or a particular set-up or radiation equipment typeemployed. Once the clinician supplies the requested additionalinformation, the reader 75 may automatically determine the radiationdose using the additional information provided. The obtained data, aswell as other information, may be stored in an electronic memory (memorydevice) included on the sensor patch (block 130).

In particular, the electronic memory may include methodology data thatinstructs the reader 75 how to interface with, i.e., obtain data from,the sensor patch(es) 30. Thus, for example, if the patch 30 changeselectronic configuration, the patch 30 can be configured toautomatically instruct the reader 75 on how to obtain the radiation andother patch data of interest, allowing the reader 75 to operate withdifferent versions of patches. In other embodiments, the reader 75 canbe periodically upgraded with software to communicate with the differentversions of patches. Combinations of these configurations may also beused.

The electronic memory may further include radiation-dose data, patientdata, time and date of a radiation reading, calibration data and thelike. Furthermore, as discussed above, the electronic memory may includethe zero temperature coefficient of a MOSFET included on the sensorpatch 30. This zero temperature coefficient may be used to bias theMOSFET after the radiation treatment before a post-radiation thresholdvoltage is obtained as discussed further below.

The sensor patch 30 does not require lead wires extending from a remotepower source or computer system to operate (i.e., is basically inactiveand/or unpowered) during irradiation. For example, where a MOSFET-basedradiation sensor circuit is used, the MOSFET is generally passive butcollects a permanent space charge as a result of the passage of ionizingradiation. After radiation exposure or at a desired evaluation time, thebiosensor(s) can be inductively powered and the MOSFET-based radiationdata can be wirelessly transferred to a remote reader.

Instead, the sensor patch 30 is configured to be a discrete patch(es)(or a patch array of sensors). In some embodiments, the patch 30 cantransmit or relay radiation data upon contact with and/or insertion intoa reader device 75 and may store data in an electronic memory deviceincluded on the sensor patch. As discussed above, in certainembodiments, the sensor patch 30 may be configured to communicatewirelessly with the reader 75. The radiation dose received by the sensorpatch 30 can be determined and used to estimate the dose received by thepatient during the radiation therapy session based on the data obtainedby the reader. The reader 75 itself can be a handheld portable unit thatmay or may not require wires to connect with a remote controller orcomputer or may use a standard communication port as will be discussedfurther below. The reader 75 can include a user input such as a touchscreen and/or keypad entry. In any event, the operations can be carriedout for each or a selected radiation treatment session. If theoperations are repeated for each treatment session, a cumulative amountof delivered radiation can be estimated/confirmed to allow a clinicianto evaluate whether additional treatments are desired.

FIG. 3A illustrates that the sensor patches 30 can be provided in a kitor set 130 including a plurality of sensors 30 p. The plurality ofsensors 30 p may be configured in sufficient numbers and/or types for asingle patient or so as to be able to supply sensors across a pluralityof patients. In certain embodiments, a strip of six sensor patches 30can be packaged together as a set 130′ as shown in FIG. 15A. It iscontemplated that, depending on the treatment type, the treatmentlocation, the tumor site, and the like, different numbers of sensorpatches 30 may be used for different patients. Thus, if the sensor kit130 is sized for a single patient, the kit may include from about 2 toabout 10 or more sensor patches 30 that can be selectively chosen foruse by the clinician. Each sensor patch 30 can be sterilized and sealedin a sterile package or the kit 130 itself can be sized and configuredto hold a plurality of the sensor patches 30 p in a sterile packagethat, once opened, can be either used or discarded. Similarly, if thesensor kit 130 is sized for multi-patient use, then larger quantitiesmay be packaged individually, or in sets within the multi-patientpackage, together. The sterilization can be performed by heat orchemical exposure, such as by ethylene oxide sterilization. In certainembodiments, sterilization and/or sterile packaging may not be required.

As is also shown in FIG. 3A, each sensor patch 30 can be packaged withpre-irradiation characterizing data 132. This data 132 can be includedin optically or electronically readable formats such as in bar codeformat for the reader to be able to read without having the clinicianenter the information into a controller/computer. In certainembodiments, the data 132 may be included in a memory storage device 67,for example, an electrically programmable memory such as an electricallyerasable read only programmable memory (EEPROM), provided on each sensorpatch 30 p as discussed further below. The memory storage device 67 mayinclude information such as patient identification, time, date,hospital, therapist, state of the device, dosed/undosed sensor data andcalibration data. The memory storage device 67 may further be used tostore bias parameters and/or information with respect to measurementmethodology for each individual patch 30. For example, the measurementmethodology may include instructions for the reader 75 on how tocommunicate with the sensor patch 30. Including these instructions inthe memory storage device may allow the reader 75 to operate with anyversion of the sensor patch 30 as the reader 75 may not have to beconfigured for the specifications of a particular sensor patch 30. Insome embodiments of the present invention, the memory storage device 67of the sensor patch 30 may have at least 2K of storage thereon.

Each sensor patch 30 can have an individual calibration coefficient,dose data or characterizing data label located on the sensor patch 30 oras a corresponding label held with the package or kit 130. In otherembodiments, each sensor patch 30 produced in a common production run(off of the same wafer or chip) with substantially similarcharacterizing data may be packaged together and a single calibrationcharacterizing data or label 132 can be included with the set 130 orsets or production run. In certain embodiments, the calibration relatedcharacterizing data can include the pre-irradiation threshold voltagevalue of a MOSFET(s) that is measured at an OEM and provided in or withthe sensor patch set 130.

In further embodiments, the memory storage device 67 may include a zerotemperature bias parameters associated with the MOSFET included on thesensor patch 30. The zero temperature coefficient of the MOSFET may bemeasured prior to administration of radiation therapy to the patient andstored in the memory storage device 67. The zero temperature coefficientof the MOSFET may be used to bias the MOSFET before obtaining apost-radiation threshold voltage value of the MOSFET as discussedfurther below.

Referring now to FIG. 19, Table 1 summarizes exemplary specificationsfor the sensor patch 30 according to some embodiments of the presentinvention. It will be understood that the specifications provided inTable 1 are provided for exemplary purposes only and that embodiments ofthe present invention should not be limited to thisconfiguration/features.

In certain embodiments, identifying indicia may be disposed on thesensor patches 30 to allow a clinician to easily visually identifyand/or account for the sensors used. For example, FIG. 3A illustratesthree discrete sensor patches labeled as 1F, 2F, and 3F as well as asensor with a pictorial representation of a heart 4F (other visualimages can also be used such as a yellow caution sign, other anatomicalsymbols, and the like). The heart or caution sensor patch 30 s can bepositioned in a radiation sensitive area to detect the amount ofradiation delivered to that area. Typically, the radiation beam isadjusted to reduce the radiation exposure to sensitive areas and acaution-sensitive sensor patch 30 s (or patches) can indicate whetheradjustments need to be made to reduce the detected exposure for each orselected treatment sessions. The sensor patches 30 s used for sensitivedetection may be configured with increased sensitivity for enhanced doseresolution capability for measuring small, residual, or stray doses ofradiation (such as those located over critical organs which are not inthe treatment volume). For example, for “normal” single use sensors maybe configured to operate over a range of between about 20-500 cGy; the“high sensitivity” sensor might be configured to operate from about 1-50cGy. In particular embodiments, the circuit 30 c (FIG. 9A) for the highsensitivity sensor 30 s includes at least one radiation-sensitivefield-effect transistor (RADFET) that can be configured to produce alarger threshold voltage shift for a given amount of received orabsorbed dose relative to the sensors 30 positioned in the window of thetargeted treatment volume. The larger voltage shift may increase doseresolution and possibly dose repeatability.

In addition, single-use dosimeters can be optimized to work over a muchlower dose range than multiple use dosimeters. Since the typical per dayfraction for radiation therapy is about 200 cGy, the dosimeter sensor 30can be optimized for accuracy and repeatability over this dose range. A20-500 cGy operating range should meet performance goals while providingadequate flexibility for varying treatment plans. A multiple-sessionfraction dosimeter sensor 30 may require a larger dose range thatdepends on the number of fractions over which the sensor will operate.As used herein, “disposable” means that the sensor patch is not reusableand can be disposed of or placed in the patient's records.

As shown in FIG. 3A, the indicia can include an alphanumeric identifiersuch as the letter “F” located to be externally visible on the sensorpatches 30. The letter “F” can represent that the sensors are placed ona first side or front of the patient. FIG. 3B illustrates that a secondset of sensors 130′ can be supplied, these sensor patches 30 can belabeled with different indicia, such as 1B, 2B, 3B and the like,representing that they are located at a different location relative tothe first set (such as a second side or back of the patient). Using datafrom opposing outer surfaces can allow an interpolated radiation doseamount to be established for the internal tumor site.

It will be understood that the indicia described above, namely “F” and“B”, are provided herein for exemplary purposes only and that indiciaaccording to embodiments of the present invention are not limited by theexamples provided. Any label, mark, color or the like may be used thatwould serve to distinguish one patch or set of patches from anotherpatch or set of patches without departing from the teachings of thepresent invention. For example, instead of “F” and “B”, the first set ofpatches 130 may be blue and the second set of patches 130′ may be red.Furthermore, the indicia may be, for example, on the sensor patch itselfor on an adhesive covering placed on or over the sensor patch withoutdeparting from the teachings of the present invention. Still further,the sensor patches 30 can be configured with a marking surface thatallows a clinician to inscribe an identifying mark thereon in situ.

FIG. 3C illustrates a patient anatomical map 150 that can be used toidentify where each of the sensor patches 30 are placed on the body ofthe patient. The map 150 may be stored in the patient chart or file. Foreach treatment session for which dose monitoring is desired, theclinician can allocate the same sensor patch identifier (“A”, “1F”, etc.. . . ) to the same location. The map 150 and/or indicia on the sensorpatches 30 can, in turn, help the clinician consistently identifywhether a particular location may have undue or deficient exposure. Forexample, if sensor patch F1 indicates a low radiation exposure, while F3indicates a relatively high exposure, and the two are positioned in thetargeted beam region, either one or both of the sensor patches 30 is notfunctioning properly, or the radiation beam may need adjustment. Usingsubstantially the same sensor patch position for successive treatmentsessions may allow cumulative radiation dose data to be obtained andcorrelated to provide a more reliable indication of dose. The clinicianmay also draw markings on the patient's skin to help align the sensorpatches 30 in relation thereto over the different treatments sessions.

In certain embodiments, the discrete sensor patches 30 can be arrangedto reside on a common substrate or to be attached to each other so as todefine known or constant distances therebetween (not shown). The sensorpatches 30 may be configured to be at the body temperature of thepatient during use or at room temperature, or temperatures in between.In certain embodiments, to establish a calculated dose amount, atemperature reading may be obtained, assumed, or estimated. In certainparticular embodiments, the temperature may impact the operationalchange if substantially different from that upon which the calibrationdata is established.

In other embodiments, the at least one sensor patch 30 can be used withother therapies that generate radiation and potentially expose a patientto radiation. By way of non-limiting example, at least one sensor patch30 can be mounted to a patient during a fluoroscopic procedure toevaluate the skin radiation exposure.

FIGS. 34A-38 illustrate that the at least one patch 30 can be amulti-sensor patch 30 m with a patch area sized to hold a plurality ofspaced apart discrete radiation sensor elements 30 ₁-30 _(n) (shown as30 ₁-30 ₁₀) thereon. Other numbers of sensors can be used. It is notedthat the discrete radiation sensor elements 30 ₁-30 _(n) can bedescribed as spaced-apart discrete radiation sensor circuits, eachhaving a respective electronic component that is used to measureradiation exposure. The radiation sensor circuits 30 ₁-30 _(n) may eachbe configured to use a single (unbiased) MOSFET as the respectiveradiation sensitive electronic component as noted above and as will bediscussed further below with respect to other sensor patches. The MOSFETand/or radiation sensor circuits can be configured to be non-poweredduring irradiation exposure. The radiation sensor circuits 30 ₁-30 _(n)may be configured to operate independently or may share some commoncomponents on the patch 30 m. For example, a digital signal processorand/or a memory component and the like may be common.

In some embodiments, the multi-sensor patch 30 m may have a surface areathat is between about 4-35 cm, more typically between about 8-20 cm, andin some embodiments can be between about 10-15 cm. In particularembodiments, the multi-sensor patch 30 m can be sized and configured tocover at least a major portion of a predicted radiation beam path (suchas a predicted/projected target fluoroscopic exposure surface area) onthe subject. The multi-sensor patch 30 m can be configured with agenerally low profile and with a releaseable liner covering a loweradhesive layer to allow for ease of securing to a patient.

The multi-sensor patch 30 m can be configured to have a greater densityof sensor elements and/or radiation sensor circuits proximate the outerperimeter as compared to a medial location. The patch 30 m can bepositioned for fluoroscopy procedures so that the medial locationgenerally aligns with the center of the beam and/or a target viewingregion in the body. As such, providing the decreased density medialregion (with a trace pattern that also is configured to reduce theradio-opaque nature of the patch in this region) can provide radiationdata without unduly obscuring the dynamic viewing and may be morecompatible with fluoroscopic procedures, as the X-ray beam is not undulyobscured by the circuit pattern on the patch. Additionally and/oralternatively, the electrical traces can be formed of a material that isless radio-opaque, such as, but not limited to, aluminum rather thancopper.

FIGS. 36 and 37B illustrate that the patch 30 m can be generallycircular. In other embodiments, the patch 30 m may be rectangular orsquare, with the outer periphery arranged with the radiation sensorelements generally circumferentially spaced apart to match the shape ofthe beam. FIG. 37A illustrates that two patches 30 m can be used, eachconfigured to be able to be closely spaced to the other. In theembodiment shown in FIG. 37A, two generally semi-circular patches 30 mcan be positioned side by side. One or both of the patches may includealignment indicia or members (not shown) to allow proximate positioning.The patches 30 m can abut or be spaced apart. In the embodiment shown inFIG. 37A, the medial location of the combination of the two strips,which can be generally described as that portion extending between thetwo strips and proximate the adjacent linear side portions of thepatches 30 m, are generally devoid of radiation circuits 30 ₁-30 _(n)and traces 30 t.

FIG. 36 illustrates that a single radiation circuit 30 ₁ is located in amedial region of the patch 30 m, while a larger number of the circuits,shown a 30 ₂-30 ₁₀, are circumferentially spaced about a perimeterregion of the patch. FIG. 37B illustrates that the center or medialregion may be devoid of any radiation circuits 30 ₁-30 _(n) and alsoshows that the radiation circuits 30 ₁-30 _(n) may be circumferentiallyas well as radially spaced apart. FIG. 37B also shows that adjacentpairs of the radiation circuits can extend to be read by a reader at acommon tab portion 36.

In some embodiments, each radiation sensor circuit on the patch 30 ₁-30_(n) can include at least one electrical trace 30 t that can be accessedby the reader 75 to obtain predetermined data (such as radiation andother data). The traces 30 t can be used to allow contact with a readerinput device. For example, the reader 75 can be configured with a seriesof pins that can contact a series of traces on the patch 30 m or thereader 75 can include a touch input, such as a pen 75 p (FIG. 6) thatcan contact a respective trace. The traces 30 t may converge to a commonedge portion of the sensor body as shown in FIG. 38. In otherembodiments, the sensors 30 ₁-30 n may be configured so that respectivetraces 30 t can be accessed at different locations on the patch 30 msuch as shown in FIGS. 34A, 35, 36 and 37A. FIG. 38 illustrates that themulti-sensor patch 30 m can include a single tab portion 36 thatinterfaces with a port in the reader 75 while FIGS. 35 and 37Billustrate that the patch 30 m can include several different tabportions 36 that can be used to allow a reader 75 to communicate witheach radiation sensor circuit 30 ₁-30 _(n). The tab portion 36 can beconfigured so that at least a portion thereof is sufficiently rigid tosustain its shape for proper electrical coupling when inserted into aport 32 in the reader 75 (FIG. 7A). The sensor patch 30 m may alsoinclude at least one electronic memory device 67 as noted above and aswill be discussed further below. As shown in FIG. 38, the multi-sensorpatch 30 m can include a shared memory element 67 (shown withoutelectrical traces for clarity). In other embodiments, as discussedbriefly above, each radiation sensor circuit 30 ₁-30 _(n) can includeits own memory element (similar to the single patch configurations asshown in FIG. 20). The multi-sensor patches 30 m can includecombinations of shared and individual radiation sensor circuit memory orother operational components.

In other embodiments, the sensors 30 ₁-30 _(n) may communicatewirelessly with port or unique signal identification bits to the reader75 so that traces are not required or so that a reduced amount of tracesmay be used. The sensors 30 ₁-30 _(n) may be spaced apart substantiallyequally over a fixed geometry on the patch 30 m so that an averageexposure dose can be calculated over the patch area. In addition, oralternatively, maxima and minima radiation exposure values at defined ormapped sensor locations can be identified as desired based on the knowngeometrical relationship between the radiation circuits 30 ₁-30 _(n).

The radiation circuits 30 ₁-30 _(n) of the multi-sensor patch 30 m (orthe other patch types) may be formed directly on the substrate or may beformed on a flex circuit. The flex circuit can define the patchsubstrate or can be attached (bonded or otherwise conformably mounted)to the substrate body of the patch. The patch may be a continuous bodyor may have apertures formed therein. The patch 30 m can be configuredto provide a substantially conformal fit. If formed directly onto thepatch substrate, the conductive traces 30 t may be provided by anysuitable process such as, but not limited to, ink spray,photolithography, and the like. The active radiation sensor element(such as a MOSFET) may be studded or mounted to the flex circuit attarget radiation circuit locations or formed directly on the flexcircuit, such as in a semiconductor substrate body.

FIG. 38 illustrates that a kit of patches 130′ can include at least oneprimary multi-sensor patch 30 m and at least one secondary patch 30. Theprimary patch 30 m can be any suitable multi-sensor configuration (suchas one or more of those described above or other suitableconfiguration). The primary patch 30 m can be configured to reside in atarget primary radiation beam path. The secondary patch 30 can beconfigured to reside outside the primary path to detect radiationscatter in sensitive regions or other desired zones. The secondary patch30 can be smaller than the primary patch 30 m. The kit 130′ can be asterile medical package of the patches 30, 30 m, which may be providedas a medical fluoroscopic or radiation sensor package. In someembodiments, each of the patches 30, 30 m can be configured to be readby a common portable reader 75.

In certain embodiments, a first set-up pre-dose verification protocolcan be carried out to deliver a first radiation dose and a firstradiation dose value can be obtained for at least one selected patch toconfirm that the radiation beam focus location is correct or suitable(or whether a sensitive area is receiving radiation). In addition, thesystem can be configured to map a dose gradient by correlating thedetermined radiation dose values at each patch location to theanatomical location on the subject of each patch.

FIG. 4 illustrates an exemplary patient dosimetry form 99, which may be,for example, a paper sheet or computer printable document. The form 99can contain an anatomical map 150 as discussed above with respect toFIG. 3C. Sicel Technologies, Inc. asserts copyright protection for theform illustrated in FIG. 4 and has no objection to reproduction of thepatent document, as it appears in the Patent and Trademark Office patentfile or records, but reserves all other rights whatsoever.

As discussed above, the map 150 may be used to identify and/ormemorialize for the patient record where each of the sensor patches 30are placed on the body of the patient during use. An anatomical map 150can be used to record the specifics of each radiation session and may beplaced in each patient's chart or file to assist the doctor and/orclinician. Patients being treated on an ongoing basis may have multipledosimetry forms 99 in their chart and/or file corresponding to eachtreatment session. As noted above, for each treatment session, theclinician can, as desired, allocate the same sensor patch identifier tothe same location aided by the map 150. As further illustrated in FIG.4, the dosimetry form 99 may further include a dosimetry plan portion152, a measurement data portion 154 and a sensor patch record portion156.

The dosimetry plan portion 152 may include the patient's name, the dateor dates the patient is scheduled for the treatment, the patient'sdoctor, and any information that may be specific to the patient or thepatient's treatment. The measurement data portion 154 may includeinformation such as the date of the treatment and the therapistadministering the treatment on that date. The sensor patch recordportion 156 may include labeled sections 158 (A, B, . . . ) giving eachpatient a discrete identifier which may correspond to sensor patchlocations (A, B, . . . ) with the identifiers indicated on theanatomical map 150. The sensor patch record portion 156 may furtherinclude dosing data, for example, target and measured doses asillustrated in FIG. 4. The sensor patch record portion 156 may furtherinclude the actual sensor patch used on the patient in each of thelabeled sections 158. As shown, the form 99 can include two separatestorage regions, namely a pre and post dose use storage region. Inaddition, the form 99 can also allow a clinician to indicate whether thesensor patch was held in the entrance and/or exit field.

In certain embodiments, the sensor patch 30 may contain a storage ormemory device 67 (FIGS. 3A, 9B), the storage or memory device on thesensor patches may be accessed to determine dosing information etc. ifthis information fails to be recorded, is misplaced or requiresverification. Furthermore, the memory device 67 included on the sensorpatch 30 may further include the data recorded in the map portion 150,the dosimetry plan portion 152 and the measurement data portion 154 ofthe dosimetry form 99. Accordingly, the memory device 67 on the sensorpatch 30 may serve as an electronic dosimetry patient record form. Itwill be understood that the dosimetry form 99 of FIG. 4 is provided forexemplary purposes only and that the present invention may provide dataand/or hold sensor patches in alternate manners without departing fromthe teachings of the present invention.

FIG. 5A illustrates the use of five primary sensor patches 30 positionedover the targeted treatment region (on the front side of the patient)and one sensor patch 30 s positioned over the heart. FIG. 5B illustratesthree primary sensors 30 located over the back surface proximate thearea corresponding to the underlying tumor site 25.

FIG. 6 illustrates a reader or data acquisition device 75′ according toembodiments of the present invention, in point contact with theunderlying sensor patch 30 in order to detect the amount of radiationthat the sensor patch 30 was exposed to during (or after) the treatmentsession. In certain embodiments, as discussed above, the sensorpatch(es) 30 can be secured to a patient's chart or dosimetry form 150and read after removal from the patient. The reader 75′ illustrated inFIG. 6 may be configured to contact a portion of an electrical circuiton the sensor patch 30 that includes a device that has an operatingcharacteristic or parameter that changes upon exposure to radiation in apredictable manner to allow radiation doses to be determined. The reader75′ can be configured with a probe 75 p that is configured toelectrically contact an electrically conductive probe region on thesensor patch 30 so as to obtain a reading in a “short” time of underabout 30 seconds, and typically in less than about 5-10 seconds, foreach of the sensor patches 30.

Referring now to FIG. 7A a sensor patch 30′ disposed in a reader or dataacquisition device 75″ according to further embodiments of the presentinvention. Sensor patches 30′ according to embodiments of the presentinvention may be adapted to be inserted into the reader 75″. Similarly,the reader 75″ is adapted to receive the sensor patch 30′. As shown, thesensor patch 30′ is formed to include a tab portion 36 that at least aportion of is sufficiently rigid to sustain its shape for properelectrical coupling when inserted into a port 32 in the reader device75″. As further illustrated in FIG. 7A, the reader 75″ may include asensor port 32 and the sensor patch 30′ may be inserted into the port 32in the reader 75″ in order to detect the amount of radiation that thesensor patch 30′ was exposed to. The port 32 can read the sensor patch30 as it is held in selected orientations in the port 32. The port 32may be configured similar to conventional devices that read, forexample, glucose strip sensors and the like. The port 32 illustrated inFIG. 7A may contain one or more electrical contacts configured tocontact one or more electrical contacts on the sensor patch 30′ toelectrically connect the reader 75″ to an electrical circuit on thesensor patch 30′. The electrical circuit on the sensor patch 30′includes a radiation-sensitive component that has an operatingcharacteristic or parameter that changes upon exposure to radiation in apredictable manner to allow radiation doses to be determined. As before,the reader 75″ may obtain a reading in under about 30 seconds, andtypically in less than about 5-10 seconds, for each of the sensorpatches 30.

The reader device 75″ can be held in a portable housing 37. It may bepocket sized and battery powered. In certain embodiments, the readerdevice 75 may be rechargeable. As shown in FIGS. 7, 15A and 15B, thereader 75 may, include a display portion 75 d, for example, a liquidcrystal display (LCD), to provide an interface to depict data to thedoctor and/or technician.

The function of the reader device 75 may be incorporated into anyportable device adapted to receive a sensor patch 30 in, for example, asensor port 32. For example, the reader 75 functionality/circuitry couldbe disposed in a personal digital assistant (PDA) that is adapted toinclude a radiation sensor port 32. The reader 75 may further include aremote computer port 33. The port 33 may be, for example, RS 232,infrared data association (IrDA) or universal serial bus (USB), and maybe used to download radiation and/or other selected data from the sensorpatch 30 to a computer application or remote computer.

As illustrated in FIG. 7B, in some embodiments, the sensor patch 30 andthe reader device 75″′ may both be equipped with a radio frequency (RF)interface and information may be shared between the reader device 75″′and the sensor patch 30 using wireless signals 38 without departing fromthe scope of the present invention.

In certain embodiments, as noted above, the sensor patch 30 includes astorage or memory device 67. In these embodiments, the reader 75 may beconfigured to obtain data stored in the memory device 67 of the sensorpatch 30 using, for example, electrical contacts on the reader 75 andthe patch 30, to transfer the data stored in the memory device 67 of thesensor patch 30. This data obtained from the sensor patch memory device67 may, for example, be stored locally on the reader 75 or be downloadedto an application on, for example, a remote computer using a port 33provided in the reader 75. The memory device 67 on the sensor patch 30may serve as a permanent record of the radiation dose and may contain areal time clock such that the obtained data may include a time and datestamp.

An exemplary block diagram of a reader 75 and a sensor patch 30including a RADFET 63 and an electronic memory 67 according to someembodiments of the present invention is provided in FIG. 20. It will beunderstood that the block diagram of the reader 75 and the sensor patch30 of FIG. 75 is provided for exemplary purposes only and embodiments ofthe present invention should not be limited to the configurationprovided therein. Furthermore, a flow diagram 2100 of FIG. 21illustrates how a number of reads, a read delay and/or a rate may modifyconversion parameters of the RADFET according to some embodiments of thepresent invention.

FIG. 8A illustrates exemplary embodiments of a sensor patch 30. Asshown, the sensor patch 30 includes a substrate layer 60, a circuitlayer 61, and an upper layer 62 that may be defined by a coating, film,or coverlay material. The substrate layer 60 can be selected such thatit is resilient, compliant, or substantially conformable to the skin ofthe patient. Examples of suitable substrate layer materials include, butare not limited to, Kapton, neoprene, polymers, co-polymers, blends andderivatives thereof, and the like. The underside or bottom of the sensorpatch 30 b may include a releasable adhesive 30 a so as to be able toattach to the skin of the patient. The adhesive 30 a can be a medicalgrade releasable adhesive to allow the sensor patch 30 to be secured tothe skin during the treatment session and then easily removed withoutharming the skin. The adhesive 30 a can be applied to portions, or all,of the bottom surface of the substrate layer 60. A releasable liner canbe used to cover the adhesive, at least prior to positioning on thepatient. In certain embodiments, the underside of the sensor patch 30 bmay be free of the adhesive. In these embodiments, an adhesive coverlay30 cl (FIG. 9C) may be placed over the body of the sensor patch 30 tosecure the sensor patch 30 to the patient. The adhesive coverlay 30 clmay be sized to extend beyond the outer perimeter of the sensorsubstrate 60. The adhesive may be on a portion or all of the undersideof the coverlay 30 cl.

In other embodiments, the sensor patch(es) 30 is configured as adiscrete, low profile, compact non-invasive and minimally obtrusivedevice that conforms to the skin of the patient. The sensor patch(es)may be less from about 0.25 to about 1.5 inches long and wide and have athin thickness of from about 1 to about 5 mm or less. As such, thesensor patches 30 can, in certain particular embodiments, be secured tothe patient and allowed to reside thereon for a plurality or all of thesuccessive treatments. For example, the sensor patches 30 can beconfigured to reside on the patient in its desired position for a 1-4week, and typically about a 1-2 week period. In this manner, the samesensor patches 30 can be used to track cumulative doses (as well as thedose at each treatment session). An adhesive may be applied in aquantity and type so as to be sufficiently strong to withstand normallife functions (showers, etc.) during this time. Of course, selectedones of the sensor patches 30 can also be replaced as desired over thecourse of treatment as needed or desired.

In certain embodiments of the present invention, the sensor patch 30 canbe attached to the patient so that it makes and retains snug contactwith the patient's skin. Air gaps between the sensor 30 and thepatient's skin may cause complications with respect to obtaining theestimated dosage data. As illustrated in FIGS. 9D and 9E, someembodiments of the present invention include the placement of an overlaymaterial 30 fl over the sensor patch 30 to, for example, simulateplacement of the sensor patch 30 beneath the patient's skin. This typeof simulation may inhibit scatter of the radiation beam and/or establishelectronic equilibrium in proximity to the sensor patch 30 and,therefore, increase the reliability of radiation measurement. Radiationmeasurement using the sensor subsurface electronics may be optimal atfrom about 0.5 to about 3 cm beneath the patient's skin, but typicallyis from about 1 to about 1.5 cm beneath the patient's skin. Accordingly,the overlay material 30 fl may be from about 0.5 to about 3 cm thick tosimulate subsurface depth measurement conditions. The presence of thisoverlay material 30 fl may decrease the influence of air gaps betweenthe sensor 30 and the patient's skin.

The overlay material 30 fl may be, for example, a resilient flubber likeor flexible material that will conform to the skin such as anelastomeric or the like. As illustrated in FIG. 9D, the overlay material30 fl may be placed between the adhesive coverlay 30 cl and the sensorpatch 30 such that the adhesive coverlay 30 cl adheres the sensor patch30 and the overlay material 30 fl to the patient's skin. As illustratedin FIG. 9E, the overlay material 30 fl may be placed over the adhesivecoverlay 30 cl and the sensor patch 30. In certain embodiments, theoverlay material may have adhesive properties such that the overlay 30fl may be adhered to the patient's skin. The overlay material 30 fl mayalso be integrated with the sensor patch 30 without departing from theteachings of the present invention.

As further illustrated in FIGS. 18A and 18B, some embodiments of thepresent invention include the placement of a buildup cap 180 over thesensor patch 30 to, for example, simulate placement of the sensor patch30 beneath the patient's skin. This type of simulation may help to focusa narrow portion of the radiation beam in proximity to the sensor patch30 and, therefore, increase the reliability of radiation measurement. Asfurther illustrated in FIG. 18A, the buildup cap 180 may have ahemispherical shape and may simulate placement of the sensor patch 30inside the body to a depth called “Dmax”. Dmax may be, for example, fromabout 1 to about 3 cm and is the depth at which the absorbed dosereaches a maximum for a given energy. The buildup cap 180 may include amaterial equivalent to water and a metallic material. For example, thebuildup cap 180 may include a layer of polystyrene 182 having a diameterof from about 6 to about 7 mm and a layer of copper 181 on thepolystyrene have a thickness of about 0.5 to about 1 mm.

The buildup cap 180 may include a small lip (not shown) that hooks ontothe front edge of the patch for consistent alignment. The buildup cap180 may have a medical grade adhesive that would stick well, but notpermanently, to the top face of the sensor patch 30. In some embodimentsof the present invention, the geometry of the cap could be made to helpwith isotropy. The buildup cap 180 may be placed on the sensor patch 30separately based on the energy range of the buildup cap 180, therebyallowing the underlying sensor patch 30 to be used with differentbuildup caps 180 for different energy ranges. In some embodiments of thepresent invention, the buildup caps 180 may be provided in differentcolors, the colors indicating the energy range of the buildup cap 180.Thus, in some embodiments of the present invention, the bulk of thebuildup cap 180 may be injection molded polystyrene 182 that is coatedwith a copper layer 181 and some rubbery or elastomeric surface paintapplied in different colors corresponding to the different energy rangesprovided by the buildup cap 180. The buildup cap 180 can also be shapedto provide a measurement that is independent of X-ray beam entry angle.

It will be understood that the buildup cap 180 may be placed between theadhesive coverlay 30 cl and the sensor patch 30 such that the adhesivecoverlay 30 cl adheres the sensor patch 30 and the buildup cap 180 tothe patient's skin. It will be further understood that the buildup cap180 may also be placed over the adhesive coverlay 30 cl and the sensorpatch 30 without departing from the scope of the present invention

Still referring to FIG. 8A, the sensor circuit layer 61 can be attachedto, and/or formed on, the underlying substrate layer 60. The upper layer62 can be configured as a moisture inhibitor or barrier layer that canbe applied over all, or selected portions of, the underlying circuitlayer 61. It is noted that, as shown, the thickness of the layers 60-62are exaggerated for clarity and shown as the same relative thickness,however the thickness of the layers may vary. In certain embodiments,the sensor patch 30 is configured as a low profile, thin device that,when viewed from the side, is substantially planar.

FIG. 8B is a top view of embodiments of a sensor patch 30. As shown, incertain embodiments, the circuit layer may include two conductive probecontacting regions 30 p. During data readings/acquisitions, the probecontacting regions 30 p are configured to provide the connectionsbetween the operating circuitry on the circuit layer 61 and the externalreader. The probe contacting region(s) 30 p can be directly accessibleor covered with a protective upper layer 62. If directly accessible,during operation, the reader 75 can merely press against, contact orclip to the sensor patch 30 to contact the exposed surface of theconductive probe region 30 p to obtain the reading. If covered by anupper layer 62 that is a protective coating or other non-conductiveinsulator material, the clinician may need to form an opening into thecoating or upper layer over the region 30 p so as to be able topenetrate into the sensor patch 30′ a certain depth to make electricalcontact between the probe region 30 p and the probe of the reader 75 p.

FIG. 8C illustrates a probe portion 75 p of the reader 75′ of FIG. 6. Asillustrated, the probe portion 75 p may be configured so that the probe75 p includes, for example, conductive calipers, pinchers, or otherpiercing means, that can penetrate to make electrical contact with theprobe contacting region 30 p of the sensor patch.

FIG. 9A illustrates a top view of embodiments of a circuit layer 61. Asshown, the circuit layer 61 includes the radiation sensitive operativesensor patch circuitry 30 c that is self-contained and devoid ofoutwardly extending or hanging lead wires that connects to anoperational member. The sensor patch circuitry 30 c includes a radiationsensitive device 63 that exhibits a detectable operational change whenexposed to radiation. In certain embodiments, the radiation sensitivedevice 63 is a miniaturized semiconductor component such as a MOSFET.Suitable MOSFETs include RADFETs available from NMRC of Cork, Ireland.In certain embodiments, the MOSFET may be sized and configured to beabout 0.5-2 mm in width and length. The circuitry 30 c also includes atleast one conductive lead or trace 64 extending from the radiationsensitive device 63 to the conductive probe contacting region 30 p. Inthe embodiment shown, the conductive probe contacting region 30 p is anannular ring. As also shown there are two traces 64 i, 64 o that connectthe device 63 to the ring 30 p. The traces or leads 64′ may be formed,placed, or deposited onto the substrate layer 60 in any suitable mannerincluding, but not limited to, applying conductive ink or paint or metalspray deposition on the surface thereof in a suitable metallic pattern,or using wires. As desired, an upper layer 62 such as described above(such as epoxy) may be formed over the circuit layer 61 (or even theentire sensor patch). The sensor patch 30 may include integrated ElectroStatic Discharge (ESD) protection, the reader 75 may include ESDprotection components, or the user/operator may use ESD straps and thelike during readings.

In particular embodiments, the sensor patch 30 and circuit 30 c can beconfigured with two or more MOSFETS. In embodiments configured to havetwo MOSFETS, one may be positioned over the other on opposing sides ofthe substrate in face-to-face alignment to inhibit orientation influenceof the substrate. (not shown). Additionally, other materials, e.g.,certain epoxies, can be used to both encapsulate the MOSFETs and providefurther scattering influence to facilitate isotropic response of theMOSFETs. In addition, there are well known influences of radiationbackscatter from the surface of patients on whom surface-mounteddosimeters are used. The backscatter effect can be taken into accountwhen calculating an entrance or exit dose or sufficient build-up may beprovided on the top of the dosimeter to promote the equilibration ofscattered electrons. See, Cancer, Principles and Practice of Oncology,3d edition, ed. V T DeVita, S. Hellman, and S A Rosenberg (JB LippincottCo., Phila., 1989), the contents of which are hereby incorporated byreference as if recited in full herein.

FIG. 9B is a top view of further embodiments of a sensor patch 30′ thatincludes a tab portion 36 that is adapted to be received by a reader,for example, reader 75″ illustrated in FIG. 7. As shown, the circuit 30c′ includes a circuit layer 61 that includes at least one electricalcontact 31 shown as a plurality of substantially parallel leads. Duringdata readings/acquisitions, the sensor patch 30′ is inserted into thereader port 32 of the reader 75″ (FIG. 7) and the at least oneelectrical contact 31 is configured to provide the electricalconnections between the operating circuitry on the circuit layer 61 andthe external reader 75″. The electrical contact(s) 31 may be coveredwith a protective upper layer 62 (FIG. 8A). If covered by an upper layer62 that is a protective coating or other non-conductive insulatormaterial, the clinician may need to form an opening into the coating orupper layer over the electrical contact(s) 31 so these contact(s) 31 maymake electrical contact with the reader via sensor port 32 (FIG. 7).

FIG. 9B further illustrates the circuit layer 61 that includes theradiation sensitive operative sensor patch circuitry 30 c′. The sensorpatch circuitry 30 c′ includes a radiation sensitive device 63 thatexhibits a detectable operational change when exposed to radiation andmay include a memory device 67. In certain embodiments, the radiationsensitive device 63 is a miniaturized semiconductor component such as aMOSFET. Suitable MOSFETs include RADFETs available from NMRC of Cork,Ireland. In certain embodiments, the MOSFET may be sized and configuredto be about 0.5-2 mm in width and length. The circuitry 30 c′ alsoincludes at least one conductive lead or trace 64′ extending from theradiation sensitive device 63 and/or the memory device 67 to the atleast one electrical contact(s) 31. The traces or leads 64′ may beformed, placed, or deposited onto the substrate layer 60 in any suitablemanner including, but not limited to, applying conductive ink or paintor metal spray deposition on the surface thereof in a suitable metallicpattern, or using wires. As desired, an upper layer 62 such as describedabove (such as epoxy) may be formed over the circuit layer 61 (or eventhe entire sensor patch). Each sensor patch 30 may be from about 0.25 toabout 1.5 inches long and wide and have a thin thickness of from about 1to about 5 mm or less.

As discussed above with respect to FIG. 8A, the underside or bottom ofthe sensor patch 30 b may include a releasable adhesive 30 a so as to beable to attach to the skin of the patient. The adhesive 30 a can be amedical grade releasable adhesive to allow the sensor patch 30 to besecured to the skin during the treatment session and then easily removedwithout harming the skin. The adhesive 30 a can be applied to portions,or all, of the bottom surface of the substrate layer 60. Referring nowto FIG. 9C, in certain embodiments, the underside of the sensor patch 30b may be free of the adhesive. As illustrated, an adhesive coverlay 30cl may be placed over the entire body of the sensor patch 30 to securethe sensor patch 30 to the patient. As further illustrated, the adhesivecoverlay 30 cl may be sized to extend beyond the outer perimeter of thesensor substrate 60 and leave the tab portion 36 of the sensor 30′exposed. The adhesive provided on the underside of the coverlay 30 clmay be provided on a portion of the coverlay 30 cl, for example, theportion of the coverlay 30 cl contacting the patient's skin outside theperimeter of the sensor substrate 60, or on the entire underside of thecoverlay 30 cl.

Sensor patches 30 according to embodiments of the present invention maybe provided individually or in sheets containing multiple sensor patches30. In particular, the sensor patches 30 may be fabricated inhigh-density sheets. As used herein, “high density” refers to multiplesensor patches provided on a unitary sheet. High density is intended toencompass very large sheets containing, for example, hundreds orthousands of sensors, as well as, for example, 3×3 regions of these verylarge sheets typically including 6 or more sensors per region. Providingthe sensor patches 30 including memory devices 67, for example EEPROMs,on high density sheets 200 as illustrated in FIGS. 10A through 10Dprovide the capability of calibrating and/or pre-dosing the entire sheetof sensor patches 30 at one time. As shown in FIG. 10A, the sheets 200may include perforations for subsequent separation of the individualsensor patches 30 from the high density sheet 200. In certainembodiments, the sheet of sensor patches 200 may include from about 30to about 100 sensor patches 30 per sheet. In other embodiments, multiplepatches 30 may be provided per square inch of the high-density sheet 200and/or multiple patches 30, typically at least 6 patches, may beprovided in a 3 by 3 inch region of the high-density sheet.

As further illustrated in FIG. 10D, in some embodiments of the presentinvention, the sensor patches 30 may be configured in an array 200′ of16×2 sensor patches. This arrangement may provide a method of processing32 patches in a single batch. Each patch may be singularized, i.e.,detached from the other sensor patches 30 in the batch, in the finalprocessing steps. In some embodiments of the present invention, thedimensions of the array may be selected so that the sheet fits within a6″ diameter cylinder, such as a cylindrical blood irradiator chamber.The final assembly may be calibrated using a research irradiator, bloodirradiator, LINAC or other radiotherapy equipment without departing fromthe teachings of the present invention. It will be understood thatcalibration techniques known to those having skill in the art may beused to calibrate the patches 30 according to some embodiments of thepresent invention.

The sensor patches 30 may be calibrated at the factory or OEM. Each ofthe sensor patches 30 or the entire sheet 200 of sensor patches 30 maybe calibrated by providing a wire(s) 205 illustrated in FIG. 10B thatelectrically couples each of the sensor patches 30 on the sheet 200. Forease of reference, only a single electrical line to one sensor is shownon FIG. 10B. The calibration data may be provided to the sensor patches30 through the wire(s) 205 and may be stored in the memory storagedevice 67 of the sensor patch 30. The ability to calibrate a pluralityof sensor patches 30 simultaneously may provide more precision in thedosimetry process and, therefore, possibly more reliable results. Itwill be understood that the sensor patches 30 may each have a dedicatedwire or the sheet can have a calibration line all connected to a commonlead 206 as shown in FIG. 10C that may be used to calibrate and/orpre-dose the sensor patches 30 individually.

As discussed above, the sensor patches 30 may be pre-dosed, i.e. dosedprior to placement on the patient. Dosing a sensor patch may include,for example, setting the amount of radiation to be delivered to apatient and the particular region(s) on the patient to which theradiation should be delivered. This process is typically performed by aphysicist and can be very time consuming. The possibility of accuratelypre-dosing a sensor patch 30 may significantly reduce the need for aphysicist to be involved in the dosimetry confirmation process. In otherwords, using reliable dose patches can reduce the time a physicistexpends to confirm the treatment beam and path dose.

It will be understood that sensor patches 30 adapted to be received by areader 75 are not limited to the configuration illustrated in thefigures provided herein. These figures are provided for exemplarypurposes only and are not meant to limit the present invention. Forexample, the sensor patch 30′ of FIG. 9B can be configured with ageometry that allows it (entirely or partially) to be received by areader 75″. The insertable geometry may take the form of an elongatedtab, one end of the tab containing the radiation sensitive circuitry aswell as the memory and the other end of the tab containing theelectrical contacts for insertion into the reader device (not shown).

Some embodiments of the present invention provide a test strip 2200 asillustrated in FIG. 22. The test strip 2200 may allow the functionalityand calibration of the reader 75 to be tested and verified. According tosome embodiments of the present invention, the test strip 200 mayconsist of a sensor patch including an EEPROM and a resistor and avoltage reference instead of the MOSFET/RADFET. Thus, in the event thatthe reader 75 is, for example, left in the radiation treatment beam, hasa mechanical failure or the like, a 4.096 V reference or a currentsource may be altered and, therefore, may yield incorrect dose readings.The test strip 2200 may provide an external reference that may be usedto verify proper operation and calibration of the reader 75.

As stated above, the test strip 2200 may be similar to the sensor patch30 except the RADFET may be replaced with a series combination of avoltage reference and a resistance, for example, a 1.2V shunt reference(specified at 0.1% tolerance such as an LM4051-1.2) and a 10 KΩ resistor(0.1% tolerance). In some embodiments of the present invention, thegate/drain connection may have a 39 KΩ, 0.1% tolerance resistor coupledto ground on the test strip 2200. The 39 KΩ resistor may provide anadditional 52 μA bias to the series 1.2V reference and 10 KΩ resistor.

The test strip 2200 may include a memory map, which may include, amongother things, the defaults from the base load (at the ZTC process), i.e.the pre-radiation data. Table 7 of FIG. 31 contains a listing offunctional specifications of test strips according to some embodimentsof the present invention. It will be understood that the functionalspecifications listed in FIG. 31 are provided for exemplary purposesonly and that embodiments of the present invention are not limited tothis configuration.

The reader 75 may interrogate the test strip memory and request that adoctor technician perform a “zeroing operation” discussed further below.The test strip 2200 may be zeroed and the resulting digital to analogconversion (DACB) value may be compared to the DACB value determined atthe factory. The result may indicate, for example, “Reader OK” if theDACB value is within a set of limits provided or “Reader needs Cal” ifthe DACB value is outside the set of limits. It will be understood thatthe limits may be determined on a per-reader basis during factorycalibration.

In certain embodiments of the present invention, the test strip 2200 maybe configured to prevent modification by the reader 75. In someembodiments of the present invention, the reader may be configured toindicate “Reader OK” when the test strip 2200 is inserted and apredetermined reference voltage, such as about 4.096 V, is within apredetermined range. The reader may be further configured to indicate“Reader needs Cal” if the reference voltage is outside of thepredetermined range. In some embodiments of the present invention, thepredetermined range may be from about 4.075 to about 4.116V. Thetolerance on the limits may be about +/−0.005V

As shown in FIG. 11, in certain embodiments, the patch radiationsensitive device 63 is a RADFET. The RADFET can be biased with agate/drain short so that it acts as a two-terminal device. FIG. 11illustrates a portion of the circuit 30 c with a RADFET 63 and twoassociated reader 75 interface or contact points 63I₁, 63I₂. FIG. 12Aillustrates a reader 75 (upper broken line box) and the circuit 30 c(lower broken line box) with the RADFET 63 configured with a gate todrain short. As shown, the reader 75 can include a RADFET bias circuit75 b that includes a controlled current source to allow a voltagereading to be obtained corresponding to the threshold voltage of theRADFET.

As shown by the graph in FIG. 12B, changes in surface state chargedensity induced by ionizing radiation causes a shift in thresholdvoltage in the RADFET. FIG. 12B illustrates a radiation response of astandard P210W2 400 nm implanted gate oxide RADFET with lines for 0V(the -0- marked line) and 5V (the line with the -*- markings)irradiation bias responses. To obtain the amount of threshold voltage(“Vth”) shift, the Vth value (zero dose) can be subtracted from thepost-irradiation value and the calibration curve used to determineradiation dose. The calibration curve can be pre-loaded into thecontroller of the reader or a computer to provide the dose data. Incertain embodiments, when obtaining the readings, the clinician may weargrounding straps to reduce static sensitivity of the circuitry. Incertain embodiments, such as where contact points are exposed, ESDprotection may be integrated into the sensor patch 30 itself.

As shown in FIG. 12A, the Vth change can be measured by determining thechange in applied gate voltage necessary to induce a set current flow.As noted above, the RADFET characterization data can be obtained priorto exposure to radiation (zero dose). Thus, the starting thresholdvoltage of the sensor patch 30 will be known from a priori information(or can be obtained by the clinician prior to placing on the patient orafter on the patient but before radiation exposure) and can be placed inthe reader 75 or computer associated or in communication therewith.

FIG. 13 illustrates the threshold voltage relationship between outputvoltage (voltage) and current Ids (the electrical current, drain-tosource, in microamps) as measured using the output voltage of the readercircuit shown in FIG. 12A. In operation, the reader circuit isconfigured to contact the sensor to provide a constant current source tothe circuit so as to be able measure Vth at a substantially constant orfixed bias condition.

In some embodiments of the present invention, the zero temperaturecoefficient of the MOSFET/RADFET 63 (FIG. 11) may be obtained. The zerotemperature coefficient of a MOSFET refers to a specific bias currentlevel at which the threshold voltage of the MOSFET does not changesignificantly with temperature variation in the range of temperatureslikely to be encountered according to some embodiments of the presentinvention. Although the zero temperature bias current typically variesfrom one MOSFET to another, it is a parameter that may be measuredbefore the administration of radiation therapy to the patient andstored, for example, in the memory device 67, along with thepre-radiation threshold voltage of the MOSFET measured when the MOSFETis biased with the zero temperature bias current. After recording andstoring these parameters, the patch 30 may be exposed to radiation andinserted into the reader 75 or wirelessly coupled to the reader 75. TheMOSFET may be biased with the stored zero temperature bias current(which the reader 75 may obtains from the memory device 67) and thepost-radiation threshold voltage of the MOSFET may be measured. Thechange in the threshold voltage, i.e., the difference between thepre-radiation threshold voltage and the post-radiation thresholdvoltage, may be used by the reader 75 to calculate the radiation dose.It will be understood that in these embodiments of the present inventionthe MOSFET is not operated in a biased configuration or otherwisepowered during the radiation treatment session.

The memory device 67 on the patch 30 may include a memory mapidentifying memory locations and contents thereof. In some embodimentsof the present invention, the memory map may resemble a spreadsheet. Thememory map may include one or more fields containing data, such asserial numbers, calibration factors, dose records, time stamps, biasingparameters, factory calibration information and the like. The reader 75may access data stored in the memory map using, for example, a standardI2C protocol as discussed further below. Details with respect to memorymaps will be understood by those having skill in the art and will not bediscussed further herein.

In some embodiments of the present invention, the dose may be calculatedusing Equation 1 set out below:

Dose=k _(energy) *k _(rate) *k _(SSD) *k _(fieldsize) *k _(temp) *k_(wedge) *k _(fade) *[a(v _(shift))³ +b(v _(shift))² +c(v_(shift))+d]  (Equation 1)

V_(shift) is the voltage difference (as seen by the 24-bit A/Dconverter) between the pre-radiation and post-radiation thresholdvoltage when measured at the zero temperature coefficient current(I_(BiasZTC)) discussed below. k_(energy) (Energy), k_(rate) (DoseRate), k_(SSD), k_(fieldsize) (Field Size), k_(temp) (Temperature),k_(wedge) (Wedge Angle), k_(fade) (Fade Time) (See FIG. 25) and/or othercorrection factors (collectively the “k-factors”) may be stored inmemory locations of the memory map stored in the electronic memory 67.In some embodiments of the present invention, if a coefficient isrequired, the reader may prompt the user for the coefficient during thezeroing operation. A calibration curve illustrating a dose response ofan exemplary MOSFET/RADFET according to some embodiments of the presentinvention is provided in FIG. 23. It will be understood that thecalibration curve provided in FIG. 23 is provided for exemplary purposesonly and that embodiments of the present invention are not limited bythis example.

As necessary, correction factors may be applied for energy, dose rate,field size, temperature, wedge factors, fading or other user-definedcorrections. The reader 75 can be configured to provide automaticprompts to a user or a station to obtain the desired patient-specific orequipment inputs. Coefficients for the correction factors may be storedin the electronic memory 67 of the patch 30. User-input correctionfactors may also be stored in the reader 75 non-volatile memory and maybe copied into the electronic memory 67 of the patch 30 as a record ifthe correction factors are used in the dose calculation. A graph set outin FIG. 24 illustrates and an exemplary correction factor for energydependence. It will be understood that the graph provided in FIG. 24 isprovided for exemplary purposes only and that embodiments of the presentinvention are not limited by this example.

Referring to FIG. 24, the correction factors are curve-fitted to a3rd-order polynomial and the coefficients may be stored in the memorycell locations of the memory map in the electronic memory 67 of thepatch 30. In some embodiments of the present invention, the defaultvalues may be 0, 0, 0, 1 for a, b, c, and d, respectively. Table 2 ofFIG. 25 sets out exemplary “k-factors”, discussed above, that may beapplied to the dose equation set out in Equation 1 above.

In particular, temperature correction factor coefficients may be storedin the memory locations of the memory map stored in the electronicmemory 67 of the patch 30. In some embodiments of the present invention,the temperature correction factor coefficients may be stored in afloating point format. The coefficients may be stored in the orderillustrated in Table 3 of FIG. 26 illustrating temperature correctioncoefficient locations.

The standard temperature may be normalized to about 20° C. Thecorrection factors may be curve-fitted to a 3rd-order polynomial and thecoefficients may be stored in the memory map of the patch 30. Thedefault values may be, for example, set to 0, 0, 0, 1 for a, b, c, andd, respectively. The input to the equation may be the temperature in °C. determined by calculating the temperature (° C.). This is calculatedfrom the difference in a diode reference voltage and a diode voltagemeasured during the post-radiation process. The difference may bemultiplied by the diode temperature coefficient stored in the memory 67and added to 27° C. plus 1/10th of T_(Offset) discussed below.

For example, the patch temperature may be determined according toEquations 2 and 3 set out below:

V _(Diode)=2.048−(V _(ADC) _(—) _(Diode)−800000h)*4.096/224  (Equation2)

Temperature=27+10*(T _(offset))+(V _(Diode)−Diode VoltageReference)/Temp Coeff. of the Diode  (Equation 3)

Furthermore, fade correction factor coefficients, i.e., coefficients ofthe correction factors for fading of the RADFET voltage, may be storedin the memory locations of the memory map stored in the electronicmemory 67 of the patch 30. In some embodiments of the present invention,the fade correction factor coefficients may be stored in a floatingpoint format. The coefficients may be stored in the order illustrated inTable 4 of FIG. 27 illustrating fade correction coefficient locations.

The standard time may be normalized to about 300 seconds (5 minutes).The correction factors may be curve-fitted to a 3rd-order polynomial andthe coefficients may be stored in the respective locations in the patchmemory 67. The default values may be set to 0, 0, 0, 1 for a, b, c, andd, respectively. The input to the dose equation (Equation 1) is thedifference in time (seconds) between the Dose-End timestamp and theReading Time versus the 300 second normalized time. For example, if thereading takes place 5 minutes and 30 seconds after the dose end time,the input to the dose equation (Equation 1) would be 30 seconds. If thereading takes place 4 minutes after the dose end time, then the input tothe equation would be −60 seconds.

In some embodiments of the present invention, the user may be promptedto input, such as via a touch sensor or a keypad, to indicate the end ofthe dose treatment. If there are multiple fields of radiation involved,the user may be instructed to press the timestamp button during the lasttreatment field. The time difference may be calculated (in seconds)between the dose end time and the reading time and may be used tocorrect for fade. If the prompt for dose time is not configured (in thereader) then the Zero-reading time plus 300 seconds may be used as thedose end time. A graph set out in FIG. 28 illustrates an exemplaryresponse for fade in the RADFET voltage following a dose application.

The cells of the memory map may further include a standardized hex-codedD/A Converter value that may be used to bias the RADFET 63 to thefactory-determined zero temperature bias current (ZTC). The value of theZTC current may be determined at the factory and may be stored in thememory device 67 during the calibration process for each individualsensor. The value that may be stored in the memory device 67 is the D/Avalue and would be written if the particular reader reference voltages,D/A (assume 16-bit), resistor values, offset voltages and bias currentsare ideal. For example, if the factory determined ZTC current is:

i_(Bias) _(—) _(ZTC)=10.00 μA  (Equation 4)

The value of the ZTC current stored in the memory device 67(I_(BiasZTC)) during the calibration process for each individual sensormay be calculated using Equation 5 set out below.

I _(BiasZTC)((V _(4.096) −i _(Bias) _(—) _(ZTC) *R _(Bias))/V_(4.096))*2¹⁶  (Equation 5)

In some embodiments of the present invention, the parameters used inthis calculation may be: V_(4.096)=4.096 V, V_(2.048)=2.048 V andR_(Bias)=10.00 KΩ. Inserting these values into Equation 5, I_(BiasZTC)may be 79 C0_(H).

The actual DAC value that may be used for a particular reader 75 dependson the reader calibration coefficients. The actual DAC value may beadjusted so that the effects of the non-ideal, such as 4.096 and 2.048VDC references, 10.00 KΩ resistor, op-amp input offset voltage and/orbias current of each particular reader 75 may be corrected. In someembodiments of the present invention, the reader calibrationcoefficients for the I_(BiasZTC) current are “I_(Bias) _(—) _(Offset)”and “I_(Bias) _(—) _(Gain)” as may be stored in a memory location of thereader 75 and may be determined during factory calibration. The actualvalue written to a particular reader DAC may be calculated usingEquation 6 set out below:

Ibias-ztc_(reader(x)) =I _(BiasZTC) *I _(Bias) _(—) _(Gain) +I _(Bias)_(—) _(Offset)  (Equation 6)

Table 5 of FIG. 29 includes exemplary V/I relationships of readersdetermined during calibration according to some embodiments of thepresent invention. It will be understood that the V/I relationships setout in Table 5 are provided for exemplary purposes only and embodimentsof the present invention are not limited to this configuration.

In some embodiments of the present invention, the bias current accuracyfor any individual reader 75 may be specified at about +/−100 nA. Thetrans-conductance of the RADFET may be specified at about 1/100 KΩ maxat the ZTC bias current. If the bias current changes between the“pre-radiation” and “post-radiation” dose readings due to, for example,switching readers, there may be a potential voltage error of about 100nA*100KΩ=10 mV. Since the initial sensitivity of the RADFET may bespecified at about 0.25 mV/cGy, this represents a potential 40 cGyerror. The specified error for the system may be about +/−1 cGy for a 20cGy dose. The repeatability of the bias current (between “pre” and“post” dose measurements) on an individual reader 75 may be specified atabout +/−1 nA so that the error due to a “trans-conductance effect” maybe limited to about 1 nA*100 KΩ=100 μV.

The reader 75 may initially “zero” an un-dosed sensor patch 30 byadjusting the output of a digital to analog converter (DAC) so that theanalog to digital (A/D) converter input is near zero. The DAC is thestandardized bias current setting that may be used for the A/D readingsfor the pre-radiation and post-radiation threshold voltage measurements.The “zeroed” value may be stored in the electronic memory 67 and thepatch status register may be updated to indicate that the patch has been“zeroed”. The zeroing operation may limit the range of the RADFET biascurrent source. After the patch has been dosed and reinserted, thereader 75 may reset the DAC-B channel to a previous level using datastored in the memory location of the electronic memory 67 so that thevoltage measured by the A/D converter may represent the shift in voltagedue to radiation. The scaling may be arranged in hardware so that thevoltage generated by the DAC-B is approximately ⅓ of the thresholdvoltage at the RADFET. The A/D conversion result and the standardizedbias current (DAC or DAC-A) may be stored in cells of the electronicmemory 67.

The Digital-to-Analog Converter (DAC) may provide two functions. Thefirst is to establish the bias current in the RADFET based on afactory-derived bias current setting. This current may be established sothat there is a minimum influence of temperature on the RADFET thresholdvoltage. The second DAC, OFFSET DAC, may provide a means to offset theRADFET initial threshold voltage in the “zeroing” procedure. In otherwords, prior to dosing, the patch may be zeroed by adjusting the OFFSETDAC so that the output of the summing amplifier is about 2.048V+/−100 mVwhen the patch RADFET is connected. The summing amplifier subtracts thevoltage from the OFFSET DAC from the RADFET and applies the differenceto the A/D Converter. This DAC setting may be stored in electronicmemory 67 of the patch 30 and reused after dose is applied to bias theRADFET. The difference in the pre-dose and post-dose RADFET thresholdvoltages measured by the A/D Converter may be used to calculate themeasured dose.

The memory map may also include a memory cell including T_(offset),which may be, for example, a byte representing the temperature at whichthe diode voltage of the RADFET may be measured. In some embodiments ofthe present invention, the offset may be based on a nominal temperatureof about 27.0° C. Accordingly, if, for example, the actual temperatureduring the RADFET diode measurement (during the ZTC process) is 27.0°C., then the offset will be 00h.

In some embodiments of the present invention, the diode voltage may bemeasured (at the I_(Bias) _(—) _(Diode) current) during ZTC processingand the voltage may be converted to hexadecimal notation using Equation7 set out below.

V _(Diode@Temp)=800000h+(2.048−V_(Diode(measured)))*2²⁴/4.096  (Equation 7)

This value may be stored in memory locations of the memory map in theelectronic memory 67.

As noted above, the MOSFET bias parameters, along with customizedcalibration coefficients, are stored in the EEPROM memory provided oneach patch. The patch memory also includes a patch identifier or serialnumber, and instructions on how the reader interfaces with the patch.Provision of these instructions allows the reader to work with multiplegenerations of patches without necessitating upgrades to the reader. Thepatch memory also stores the detected and calculated radiation dosages,the date and time of the treatment, and a clinician-entered patientidentifier and/or record number. After use, the patch can be placed inthe patient file or medical record to form a part of the archivedpatient treatment history, or may be discarded.

FIGS. 14A and 14B illustrate alternate embodiments of MOSFET basedcircuits 30 c. Each circuit 30 c employs a RADFET pair 63 p (FIG. 14A),63 p′ (FIG. 14B) as the radiation sensitive device 63. The configurationon the left of each of these figures illustrates the irradiationconfiguration and the configuration on the right illustrates the readdose configuration. In the embodiment shown in FIG. 14A, the RADFET pair63 p are differentially biased during irradiation to create differentvoltage offsets. Each of the RADFETs in the pair 63 p ₁, 63 p ₂ can bedifferentially biased during radiation to generate different voltageoffsets when exposed to radiation. Using a pair of RADFETS can reducethe influence of temperature in the detected voltage shift value. Inparticular embodiments, the RADFET pair can be matched (such as takenfrom the same part of the substrate during fabrication) to reduce drifteffects (Vth drift). In certain embodiments, the voltage reading can beobtained with a zero bias state, and/or without requiring wires duringradiation, and/or without requiring a floating gate structure.

In the embodiment shown in FIG. 14B, one of the RADFETs 63 p ₁′ in thepair 63 p is selectively implanted with dopant ions to shift thethreshold voltage (Vth) of that RADFET with respect to the other RADFET63 p ₂′. The ion implantation can be carried out in various manners asknown to those of skill in the art, such as by masking one of the FETswith photoresist to inhibit ions from entering into the gate region. Asis well known, using the proper implant species and/or dopant materialcan increase the FET sensitivity to radiation effects. In certainembodiments of the present invention, a MOSFET (RADFET) pair is used toeffectively provide “differential biasing” without the need to apply anexternal voltage and without the need for a floating gate structure.That is, the MOSFETs can be configured to be individually unbiased andreadings of the two MOSFETs (one at a different threshold voltage value)generates the differential biasing. In particular embodiments, thisradiation sensitive MOSFET pair configuration that does not requirefloating gate structures and/or external voltage can be used inimplantable as well as skin mounted sensors, such as in implantablesensors used as described in U.S. Pat. No. 6,402,689 to Scarantino etal.

FIG. 15A illustrates embodiments of a radiation dose evaluation system15 according to embodiments of the present invention. As shown, thesystem 15 includes a reader 75 and a set of radiation sensor patches130′. The reader 75 may include, for example, the reader 75′ of FIG. 15Bor the reader 75″ of FIG. 15C. The sensor patches 30 can be arranged asa strip of patches 30 held in a single-patient sized package 130 p. Asbefore, the package 130 p may also include bar coded radiationcalibration characterizing data labels 132 for the sensor patches 30and/or a memory 167 in each or selected memory patches 30. The reader75′ as shown in FIG. 15B can include the probe 75 p, an optical wand 75w and a display screen 75 d. The reader 75″ as shown in FIG. 15C caninclude a sensor port 32 and a display screen 75 d. The reader 75 canalso include a RADFET bias circuit 75 b. In certain embodiments, thereader 75 is a portable flat pocket or palm size reader that a cliniciancan carry relatively non-obtrusively in his/her pocket or a similarsized casing.

As shown by the dotted line boxes in FIG. 15A, the reader 75 may hold apower source 78 and plurality of operational software modules including:an optical bar code reader module 76, a zero-dose threshold voltage datamodule 77, a radiation dose conversion module (based on a predeterminedvoltage threshold to radiation dose response curve) 79, and a thresholdvoltage post radiation data module 80.

In operation, the reader 75 can be configured to supply a bias currentto the RADFET by attaching to the sensor patch 30 and electricallycontacting the conductive probe region 30 p or the electrical contacts31. The reader 75 can measure the voltage shift response of the RADFETon the sensor patch 30 and calculate radiation dose based on the shiftand the dose conversion algorithm. The reader 75 can display the resultsto the clinician (such as on an integrated LCD screen 75 d incorporatedinto the body of the reader) and may be configured to download or uploadthe data to another device (such as a computer or computer network) forelectronic record generation or storage.

The reader may include an electronic memory map identifying memorylocations and contents thereof. In some embodiments of the presentinvention, the memory map may resemble a spreadsheet. The memory map mayinclude one or more fields containing data, such as serial numbers,revision number, reader calibration data, A/D gain correction, A/Doffset correction, D/A gain correction, D/A offset correction, hospitalID and the like. In some embodiments of the present invention, thereader memory may be large enough to store 250 dose records of about 64bytes each. The dose record may include items listed in Table 6 of FIG.30. It will be understood that the dose record of FIG. 30 is providedfor exemplary purposes only and embodiments of the present inventionshould not be limited to this configuration. Details with respect tomemory maps will be understood by those having skill in the art and willnot be discussed further herein.

The dose amount can be calculated for each sensor patch 30 used. Inparticular embodiments, the system can be configured to generate anaverage or weighted average of the dose amount determined over aplurality of the patches. In certain embodiments, where there is a largevariation in values (or if it departs from a statistical norm orpredicted value) the system can be configured to discard that sensorvalue or to alert the clinician of potential data corruption. Of course,much smaller values are predicted in sensitive areas away from thetargeted zone and the system can be configured to evaluate whether thesensor is in a primary location or in a secondary zone as regards theradiation path.

It is noted that features described with respect to one embodiment ofthe sensor, reader and/or system may be incorporated into otherembodiments and the description and illustrations of such features arenot be construed as limited to the particular embodiment for which itwas described.

As will be appreciated by one of skill in the art, the present inventionmay be embodied as a method, data or signal processing system, orcomputer program product. Accordingly, the present invention may takethe form of an entirely hardware embodiment or an embodiment combiningsoftware and hardware aspects. Furthermore, the present invention maytake the form of a computer program product on a computer-usable storagemedium having computer-usable program code means embodied in the medium.Any suitable computer readable medium may be utilized including harddisks, CD-ROMs, optical storage devices, or magnetic storage devices.

The computer-usable or computer-readable medium may be, for example butnot limited to, an electronic, magnetic, optical, electromagnetic,infrared, or semiconductor system, apparatus, device, or propagationmedium. More specific examples (a non-exhaustive list) of thecomputer-readable medium would include the following: an electricalconnection having one or more wires, a portable computer diskette, arandom access memory (RAM), a read-only memory (ROM), an erasableprogrammable read-only memory (EPROM or Flash memory), an optical fiber,and a portable compact disc read-only memory (CD-ROM). Note that thecomputer-usable or computer-readable medium could even be paper oranother suitable medium, upon which the program is printed, as theprogram can be electronically captured, via, for instance, opticalscanning of the paper or other medium, then compiled, interpreted orotherwise processed in a suitable manner if necessary, and then storedin a computer memory.

Computer program code for carrying out operations of the presentinvention may be written in an object oriented programming language suchas LABVIEW, Java7, Smalltalk, Python, or C++. However, the computerprogram code for carrying out operations of the present invention mayalso be written in conventional procedural programming languages, suchas the “C” programming language or even assembly language. The programcode may execute entirely on the user's computer, partly on the user'scomputer, as a stand-alone software package, partly on the user=scomputer and partly on a remote computer or entirely on the remotecomputer. In the latter scenario, the remote computer may be connectedto the user=s computer through a local area network (LAN) or a wide areanetwork (WAN), or the connection may be made to an external computer(for example, through the Internet using an Internet Service Provider).

FIG. 16 is a block diagram of exemplary embodiments of data processingsystems that illustrate systems, methods, and computer program productsin accordance with embodiments of the present invention. The processor310 communicates with the memory 314 via an address/data bus 348. Theprocessor 310 can be any commercially available or custommicroprocessor. The memory 314 is representative of the overallhierarchy of memory devices containing the software and data used toimplement the functionality of the data processing system. The memory314 can include, but is not limited to, the following types of devices:cache, ROM, PROM, EPROM, EEPROM, flash memory, SRAM, and DRAM.

As shown in FIG. 16, the memory 314 may include several categories ofsoftware and data used in the data processing system 305: the operatingsystem 352; the application programs 354; the input/output (I/O) devicedrivers 358; a radiation estimator module 350; and the data 356. Thedata 356 may include threshold voltage data 340 (zero dose and postirradiation dose levels) which may be obtained from a reader dataacquisition system 320. As will be appreciated by those of skill in theart, the operating system 352 may be any operating system suitable foruse with a data processing system, such as OS/2, AIX, OS/390 orSystem390 from International Business Machines Corporation, Armonk,N.Y., Windows CE, Windows NT, Windows95, Windows98, Windows2000 orWindows XP from Microsoft Corporation, Redmond, Wash., Unix or Linux orFreeBSD, Palm OS from Palm, Inc., Mac OS from Apple Computer, orproprietary operating systems. The I/O device drivers 358 typicallyinclude software routines accessed through the operating system 352 bythe application programs 354 to communicate with devices such as I/Odata port(s), data storage 356 and certain memory 314 components and/orthe image acquisition system 320. The application programs 354 areillustrative of the programs that implement the various features of thedata processing system 305 and preferably include at least oneapplication that supports operations according to embodiments of thepresent invention. Finally, the data 356 represents the static anddynamic data used by the application programs 354, the operating system352, the I/O device drivers 358, and other software programs that mayreside in the memory 314.

While the present invention is illustrated, for example, with referenceto the radiation estimator module 350 being an application program inFIG. 16, as will be appreciated by those of skill in the art, otherconfigurations may also be utilized while still benefiting from theteachings of the present invention.

For example, the radiation estimation module 350 may also beincorporated into the operating system 352, the I/O device drivers 358or other such logical division of the data processing system. Thus, thepresent invention should not be construed as limited to theconfiguration of FIG. 16, which is intended to encompass anyconfiguration capable of carrying out the operations described herein.

In certain embodiments, the radiation estimation module 350 includescomputer program code for estimating radiation dose based on themeasured threshold voltage shift. The I/O data port can be used totransfer information between the data processing system and the readerdata acquisition system 320 or another computer system or a network(e.g., the Internet) or to other devices controlled by the processor.These components may be conventional components such as those used inmany conventional data processing systems that may be configured inaccordance with the present invention to operate as described herein.

While the present invention is illustrated, for example, with referenceto particular divisions of programs, functions and memories, the presentinvention should not be construed as limited to such logical divisions.Thus, the present invention should not be construed as limited to theconfigurations illustrated in the figures but is intended to encompassany configuration capable of carrying out the operations describedherein.

The flowcharts and block diagrams of certain of the figures hereinillustrate the architecture, functionality, and operation of possibleimplementations of radiation detection means according to the presentinvention. In this regard, each block in the flow charts or blockdiagrams represents a module, segment, or portion of code, whichcomprises one or more executable instructions for implementing thespecified logical function(s). It should also be noted that in somealternative implementations, the functions noted in the blocks may occurout of the order noted in the figures. For example, two blocks shown insuccession may in fact be executed substantially concurrently or theblocks may sometimes be executed in the reverse order, depending uponthe functionality involved.

FIG. 17 is a block diagram illustration of one embodiment of a reader 75according to the present invention. As shown, the reader 75 includes anoperating system 422, a processor 410, a power source 456, and a useractivation/input module 460. The reader 75 can also include a RADFETinterface module 475 and a sensor patch memory interface module 478. Thereader 75 may communicate with the sensor patch memory using, forexample, a standard I2C protocol and in some embodiments may use a clockas a data line. As discussed above, in certain embodiments, the sensorpatch 30 may be configured to communicate wirelessly with the reader 75.In these embodiments, the interface module 475 may be configured toreceive wireless signals from the sensor patch 30. The reader 75 mayoptionally include a sensor patch identifier module 428 to track whichsensor patch 30 has a particular radiation dose result. The identifiermodule 428 may allow the user to input via an input keypad associatedwith the reader, an alphanumeric identifier (F1, B1, etc.) for aparticular sensor patch prior to obtaining the reading, or a bar codeidentifier or other automated identifier means can be used (such asscanning a bar code label on the sensor and the like).

The reader 75 also includes pre-radiation (zero dose) threshold voltagedata 440, post radiation threshold voltage data 441, and a radiationestimation module 458. The pre-radiation threshold voltage data 440 andthe post radiation threshold data 441 may be obtained when the MOSFET isbiased with the zero temperature bias current discussed above. The zerotemperature bias current may be obtained before the administration ofthe radiation therapy, stored in the sensor patch memory 67 (FIG. 11)and obtained by the reader using the sensor patch memory interfacemodule 478. The radiation estimation module 458 may also be configuredto extrapolate to arrive at the radiation dose delivered to the tumorsite. In some embodiments of the present invention, the radiationestimation module 458 may be further configured to prompt a doctor ortechnician for predetermined data needed to calculate or estimate theradiation dose. The predetermined data may include conversion factorsand/or correction factors associated with different versions of thesensor patches. As shown, the reader 75 may also include an optical barcode scanner module 476 to allow the reader to input the characterizingzero dose threshold voltage values by optically reading same. Similarly,calibration data can be entered via the bar the bar code scanner 476 ormemory 67 from the patches 30. Alternatively, the clinician can enterthe desired data in situ as desired.

Tables 8 and 9 of FIGS. 32A, 32B and 33 contain a listing the functionalspecification of readers and sensor patches, respectively, according tosome embodiments of the present invention. It will be understood thatthe functional specifications listed in FIGS. 32A, 32B and 33 areprovided for exemplary purposes only and that embodiments of the presentinvention are not limited to this configuration.

Although primarily described for oncologic therapies, the devices can beused to monitor other radiation exposures, particularly exposures duringmedical procedures, such as fluoroscopy, brachytherapy, and the like.

The foregoing is illustrative of the present invention and is not to beconstrued as limiting thereof. Although a few exemplary embodiments ofthis invention have been described, those skilled in the art willreadily appreciate that many modifications are possible in the exemplaryembodiments without materially departing from the novel teachings andadvantages of this invention. Accordingly, all such modifications areintended to be included within the scope of this invention as defined inthe claims. In the claims, means-plus-function clauses, where used, areintended to cover the structures described herein as performing therecited function and not only structural equivalents but also equivalentstructures. Therefore, it is to be understood that the foregoing isillustrative of the present invention and is not to be construed aslimited to the specific embodiments disclosed, and that modifications tothe disclosed embodiments, as well as other embodiments, are intended tobe included within the scope of the appended claims. The invention isdefined by the following claims, with equivalents of the claims to beincluded therein.

1. A sterile medical kit of single-use external use radiation dosimeterpatches, the kit comprising: a plurality of single-use patches, eachpatch comprising a generally conformable resilient substrate bodycomprising opposing upper and lower primary surfaces, a flex circuitwith at least one radiation sensor circuit having an operationalelectronic component that changes a parameter in a detectablepredictable manner when exposed to radiation, the flex circuit held bythe substrate body, the flex circuit also including at least oneelectronic memory configured with radiation calibration data, wherein,in position on a patient during radiation exposure, the dosimeterpatches are devoid of externally extending lead wires, and wherein thepatches are single-use dosimeter patches that adhesively secure to theskin of a patient.
 2. A kit according to claim 1, wherein the patcheshave a lower primary surface that comprises an adhesive thereon.
 3. Akit according to claim 1, wherein the disposable dosimeter patches areadapted to contact a portable reader device to electrically couple thereader device to the patch circuit.
 4. A kit according to claim 1,wherein the disposable patches are configured to communicate with aportable reader device to wirelessly relay radiation data.
 5. A kitaccording to claim 1, wherein the memory is configured to store patientspecific data and radiation data.
 6. A kit according to claim 1, whereinthe flex circuit operational electronic component that changes aparameter in a detectable and predictable manner when exposed toradiation is an unbiased MOSFET, and wherein the patch further comprisesan externally accessible tab configured to engage a portable electronicreader to transmit threshold voltage data and calibration dataassociated with the MOSFET.
 7. A kit according to claim 1, wherein theplurality of sensor patches comprises at least one primary sensor patchand at least one secondary sensor patch, wherein the primary sensorpatch has a larger surface area than the secondary sensor patch.
 8. Akit according to claim 7, wherein the primary sensor patch is sized andconfigured to reside at least partially within a target radiation beampath during a fluoroscopic procedure, and wherein the secondary sensorpatch is configured to reside outside the target beam path during thefluoroscopic procedure.
 9. A kit according to claim 7, wherein theprimary patch flex circuit comprises a plurality of spaced apartradiation sensor circuits, each having a respective single MOSFET thatis the operational component for a respective radiation sensor circuitthat changes in a detectable predictable manner when exposed toradiation, each MOSFET configured to independently detect radiation. 10.A kit according to claim 1, wherein the flex circuit comprises aluminumelectrical traces.
 11. A fluoroscopic single-use radiation dosimeterpatch comprising a generally conformable resilient body holding at leastone radiation sensor circuit with a MOSFET that changes a parameter in adetectable and predictable manner when exposed to radiation, and whereinduring irradiation, the patch is devoid of externally extending leadwires.
 12. A fluoroscopic dosimeter patch according to claim 11, whereinthe patch has a surface area that is sufficient to cover a major portionof a predicted surface exposure area associated with a target radiationbeam path, and wherein the patch comprises a plurality of spaced apartradiation sensor circuits, each having a respective MOSFET.
 13. Afluoroscopic dosimeter patch according to claim 12, wherein eachradiation sensor circuit comprises a single MOSFET, and wherein theradiation sensor circuits are spaced apart sufficiently to provide datafor a plurality of different skin radiation exposure locations over thepatch surface area.
 14. A fluoroscopic dosimeter patch according toclaim 13, wherein the patch is configured to provide data from eachradiation sensor circuit for determining maxima, minima and averageexposure over a surface area associated with the patch.
 15. Afluoroscopic dosimeter patch according to claim 13, wherein the sensorpatch radiation circuits are configured to detect radiation doses in therange of from about 1 to about 500 cGy.
 16. A fluoroscopic dosimeterpatch according to claim 15, wherein the patch is configured with a lowprofile when viewed from the side.
 17. A fluoroscopic dosimeter patchaccording to claim 16, wherein the patch is substantially planar whenviewed from the side.
 18. A fluoroscopic dosimeter patch according toclaim 12, wherein the patch has a surface area of between about 4-20 cm.19. A fluoroscopic dosimeter patch according to claim 18, wherein thepatch has a surface area of between about 8-20 cm.
 20. A fluoroscopicdosimeter patch according to claim 19, wherein the patch has a surfacearea of between about 10-15 cm.
 21. A fluoroscopic dosimeter patchaccording to claim 12, wherein the patch comprises a first radiationcircuit with a single MOSFET that is disposed generally medially on thepatch, and wherein the remainder of the radiation circuits are spacedtransversely outwardly away from the first radiation circuit.
 22. Afluoroscopic dosimeter patch according to claim 11, wherein the patchcomprises a plurality of spaced apart radiation sensor circuits, eachhaving a respective single MOSFET, with an increased density of theradiation sensor circuits positioned away from a generally mediallocation of the patch body.
 23. A fluoroscopic dosimeter patch accordingto claim 22, wherein the patch is generally circular.
 24. A fluoroscopicdosimeter patch according to claim 23, wherein a plurality of theradiation sensor circuits are circumferentially spaced apart on thepatch body.
 25. A fluoroscopic dosimeter patch according to claim 24,wherein a plurality of the radiation sensor circuits are radially spacedapart on the patch body.
 26. A fluoroscopic dosimeter patch according toclaim 11, wherein the radiation circuits each comprise at least oneconductive metal trace for communicating with a portable reader afterirradiation.
 27. A fluoroscopic dosimeter patch according to claim 11,wherein the conductive metal traces comprise aluminum.
 28. Afluoroscopic dosimeter patch according to claim 23, wherein the sensorpatch has a substantially planar profile when viewed from the side. 29.A fluoroscopic dosimeter patch according to claim 11, wherein theradiation sensor circuit includes a MOSFET that is devoid of floatinggate structures and/or is unpowered during radiation.